VR & AR Wiki - User contributions [en]

Interpupillary distance

2019-01-11T22:02:39Z

Jason VR: minor re-wording

'''Interpupillary distance''' or '''IPD''' is the distance between the pupils of your eyes. There are two types of IPDs: [[#Real IPD|Real IPD]] and [[#Virtual IPD|Virtual IPD]].

==Real IPD==
Real IPD is the actual distance between the center of your eyes' pupils in real life. Any [[Head-mounted Display]] require this measurement to accurately position the virtual camera outputs on the screen in front of the user's eyes. The outputs have to be directly in front of both of the users' eyes. Any deviation can cause [[eye strain]]. Most [[HMD]]s allow users to adjust their camera output positions to match their IPD.

Additionally, some HMDs allow the physical position of the lenses and screens to be adjusted to match the user's physical IPD.

The average IPD for humans is 64 millimeter, with a range of 54 to 72 millimeter. You can measure your IPD by measuring the distance between the center of your pupils with a ruler.

==Virtual IPD==
Virtual IPD, sometimes referred to as ICD (Inter Camera Distance) or VCS (Virtual Camera Separation), is the distance between the 2 virtual eyes (cameras) in [[Virtual Reality]]. This number can change the [[Sense of Scale]] of the objects in the virtual environment in relation to the user.

Developers can change the sense of scale by changing virtual IPD. They can cause the environment to increase or decrease in size by changing the virtual IPD.

[[Category:Terms]]

Interpupillary distance

2019-01-11T22:00:14Z

Jason VR: minor re-wording

'''Interpupillary distance''' or '''IPD''' is the distance between the pupils of your eyes. There are two types of IPDs: [[#Real IPD|Real IPD]] and [[#Virtual IPD|Virtual IPD]].

==Real IPD==
Real IPD is the actual distance between the center of your eyes' pupils in real life. Any [[Head-mounted Display]] require this measurement to accurately position the virtual camera outputs on the screen in front of the user's eyes. The outputs have to be directly in front of both of the users' eyes. Any deviation can cause [[eye strain]]. Most [[HMD]]s allow users to adjust their camera output positions to match their IPD.

Additionally, some HMDs allow the physical position of the lenses and screens to be adjusted to match the user's IPD.

The average IPD for humans is 64 millimeter, with a range of 54 to 72 millimeter. You can measure your IPD by measuring the distance between the center of your pupils with a ruler.

==Virtual IPD==
Virtual IPD, sometimes referred to as ICD (Inter Camera Distance) or VCS (Virtual Camera Separation), is the distance between the 2 virtual eyes (cameras) in [[Virtual Reality]]. This number can change the [[Sense of Scale]] of the objects in the virtual environment in relation to the user.

Developers can change the sense of scale by changing virtual IPD. They can cause the environment to increase or decrease in size by changing the virtual IPD.

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T20:09:57Z

Jason VR: /* References */ add reference

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of eye convergence, varies depending upon the content (see [http://doc-ok.org/?p=1360 HMD optical design]).

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are not close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away (as it is in common HMD design), the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation] and [https://en.wikipedia.org/wiki/Vergence vergence] temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those other focusing reflexes can be slower.

Closing one eye is one method for focusing on a nearby virtual object, if the user is having problems. With one eye closed, there is no conflict between [https://en.wikipedia.org/wiki/Vergence vergence] and the required [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation].

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

* Oliver Kreylos, [http://doc-ok.org/?p=1360 Head-mounted Displays and Lenses]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T20:09:05Z

Jason VR: change links

Vergence-accommodation conflict

2019-01-10T20:07:12Z

Jason VR: add link

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of eye convergence, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are not close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away (as it is in common [http://doc-ok.org/?p=1360 HMD design]), the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation] and [https://en.wikipedia.org/wiki/Vergence vergence] temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those other focusing reflexes can be slower.

Closing one eye is one method for focusing on a nearby virtual object, if the user is having problems. With one eye closed, there is no conflict between [https://en.wikipedia.org/wiki/Vergence vergence] and the required [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation].

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T20:00:27Z

Jason VR: re-phrasing

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of eye convergence, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are not close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away (as it is in common [[HMD]] design), the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation] and [https://en.wikipedia.org/wiki/Vergence vergence] temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those other focusing reflexes can be slower.

Closing one eye is one method for focusing on a nearby virtual object, if the user is having problems. With one eye closed, there is no conflict between [https://en.wikipedia.org/wiki/Vergence vergence] and the required [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation].

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T19:59:21Z

Jason VR: clarifying

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of eye convergence, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are not close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away (as it is in common [[HMD]] design), the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation] and [https://en.wikipedia.org/wiki/Vergence vergence] temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

Closing one eye is one method for focusing on a nearby virtual object, if the user is having problems focusing. With one eye closed, there is no conflict between [https://en.wikipedia.org/wiki/Vergence vergence] and the required [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation].

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T19:58:24Z

Jason VR: minor fix

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of eye convergence, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are not close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation] and [https://en.wikipedia.org/wiki/Vergence vergence] temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

Closing one eye is one method for focusing on a nearby virtual object, if the user is having problems focusing. With one eye closed, there is no conflict between [https://en.wikipedia.org/wiki/Vergence vergence] and the required [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation].

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T19:57:33Z

Jason VR: clarifying

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to focusing problems, visual fatigue, and eyestrain, while looking at stereoscopic imagery, and vision effects that linger even after ceasing looking at the imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of eye convergence, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are never close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation] and [https://en.wikipedia.org/wiki/Vergence vergence] temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

Closing one eye is one method for focusing on a nearby virtual object, if the user is having problems focusing. With one eye closed, there is no conflict between [https://en.wikipedia.org/wiki/Vergence vergence] and the required [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation].

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T19:54:46Z

Jason VR: add links

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to visual fatigue and eyestrain, and vision effects that linger even after ceasing looking at the stereoscopic imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of binocular disparity, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are never close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus (accommodation) based on the perceived distance to the objects (vergence) that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation] and [https://en.wikipedia.org/wiki/Vergence vergence] temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

Closing one eye is one method for focusing on a nearby virtual object, if the user is having problems focusing. With one eye closed, there is no conflict between [https://en.wikipedia.org/wiki/Vergence vergence] and the required [https://en.wikipedia.org/wiki/Accommodation_(eye) accommodation].

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T19:50:09Z

Jason VR: typo

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to visual fatigue and eyestrain, and vision effects that linger even after ceasing looking at the stereoscopic imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of binocular disparity, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are never close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus based on the perceived distance to the objects that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the image of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to accommodation and vergence temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

Vergence-accommodation conflict

2019-01-10T19:48:24Z

Jason VR: add references

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to visual fatigue and eyestrain, and vision effects that linger even after ceasing looking at the stereoscopic imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of binocular disparity, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are never close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus based on the perceived distance to the objects that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the images of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to accommodation and vergence temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

==References==

* Oliver Kreylos, [http://doc-ok.org/?p=1602 Accommodation and Vergence in Head-mounted Displays]

* Gregory Kramida and Amitabh Varshney, [https://www.cs.umd.edu/sites/default/files/scholarly_papers/Kramidarev.pdf Resolving the Vergence-Accommodation Conflict in Head Mounted Displays]

[[Category:Terms]]

VAC

2019-01-10T19:40:22Z

Jason VR: Create redirect

#REDIRECT [[Vergence-Accommodation_Conflict]]

Vergence-accommodation conflict

2019-01-10T19:38:23Z

Jason VR: links, more clarification

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object ([https://en.wikipedia.org/wiki/Vergence vergence]), and the focusing distance ([https://en.wikipedia.org/wiki/Accommodation_(eye) accomodation]) required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to visual fatigue and eyestrain, and vision effects that linger even after ceasing looking at the stereoscopic imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of binocular disparity, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are never close to the viewer.

The problem occurs because our eyes have evolved an [https://en.wikipedia.org/wiki/Accommodation_reflex accommodation-vergence reflex], which trains them to automatically adjust their optical focus based on the perceived distance to the objects that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the images of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to accommodation and vergence temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

Vergence-accommodation conflict

2019-01-10T19:32:58Z

Jason VR: re-phrasing

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object, and the focusing distance required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to visual fatigue and eyestrain, and vision effects that linger even after ceasing looking at the stereoscopic imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of binocular disparity, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the reason it's less severe, is that the 3D objects are never close to the viewer.

The problem occurs because our eyes have evolved to automatically adjust their optical focus based on the perceived distance to the objects that they are looking at. This helps make focusing quick and accurate.

When a virtual object appears to be mere inches in front of the user’s face, but the images of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt to this conflict while looking at stereoscopic imagery, leading to accommodation and vergence temporarily decoupling. At that point other focusing reflexes take over, and focusing tends to improve. Although it may be difficult to rapidly re-focus on some virtual objects, since those focusing reflexes can be slower.

The natural accommodation-vergence coupling will re-establish at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems until it does.

Vergence-accommodation conflict

2019-01-10T19:28:09Z

Jason VR: Create page

'''Vergence-accommodation conflict''', also known as '''VAC''', or '''Accommodation-vergence conflict''', occurs when your brain receives mismatching cues between the distance of a virtual 3D object, and the focusing distance required for the eyes to focus on that object. This occurs while looking at stereoscopic imagery, such as watching 3D TV/cinema, as well as in all current, traditional [[HMD]]s.

It can contribute to visual fatigue and eyestrain, and vision effects that linger even after ceasing looking at the stereoscopic imagery.

In traditional stereoscopic technologies, the virtual image is focused at a fixed depth away from the
eyes, while the depth of the virtual objects, and the amount of binocular disparity, varies depending upon the content.

The problem is less severe in 3D TV/cinema, when it is properly taken into account during content creation and display. Part of the solution is that the 3D objects are never close to the viewer.

The problem occurs because our eyes have evolved to automatically adjust their optical focus based on the perceived distance to objects that they are looking at.

When a virtual object appears to be mere inches in front of the user’s face, but the images of that object is, optically, several meters away, the user’s eyes may focus on the wrong distance, causing the virtual object to appear blurry. The same can happen when the virtual object is very far away, but the effect is less pronounced.

A person's eyes can adapt while looking at stereoscopic imagery, leading to accommodation and vergence temporarily decoupling. At that point other focusing reflexes take over, and vision tends to improve, although it may be difficult to rapidly re-focus on some virtual objects.

Accommodation-vergence coupling will re-occur at some point after taking off the [[HMD]]. Users might experience strange-feeling vision problems.

Interpupillary distance

2019-01-10T18:43:39Z

Jason VR: /* Real IPD */ mention physical adjustment

'''Interpupillary distance''' or '''IPD''' is the distance between the pupils of your eyes. There are two types of IPDs: [[#Real IPD|Real IPD]] and [[#Virtual IPD|Virtual IPD]].

==Real IPD==
Real IPD is the actual distance between the center of your eyes' pupils in real life. Any [[Head-mounted Display]] require this measurement to accurately position the virtual camera outputs on the screen in front of the user's eyes. The outputs have to be directly in front of both of the users' eyes. Any deviation can cause [[eye strain]]. Most [[HMD]]s allow users to adjust their camera output positions to match their IPD.

Additionally, some HMDs allow the physical position of the lenses or screens to match the user's IPD.

The average IPD for humans is 64 millimeter, with a range of 54 to 72 millimeter. You can measure your IPD by measuring the distance between the center of your pupils with a ruler.

==Virtual IPD==
Virtual IPD, sometimes referred to as ICD (Inter Camera Distance) or VCS (Virtual Camera Separation), is the distance between the 2 virtual eyes (cameras) in [[Virtual Reality]]. This number can change the [[Sense of Scale]] of the objects in the virtual environment in relation to the user.

Developers can change the sense of scale by changing virtual IPD. They can cause the environment to increase or decrease in size by changing the virtual IPD.

[[Category:Terms]]

Snap Turn

2019-01-05T19:37:32Z

Jason VR: minor fix

A '''Snap Turn''', also sometimes referred to as '''Click Turn''', '''Incremental Turn''', or '''Blink Turn''', is a movement style some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user attempts to turn their character through the use of a button or some other control, their character will "instantly" turn by a pre-determined amount. Often a value like 15 degrees, 30, 45, or 90 degrees.

The turn may happen with an instant view shift, or the view may turn gradually but extremely quickly (to avoid motion sickness), or [[Vignetting]] may be used.

In some VR content, this is a feature that can be turned on or off, or adjusted as to how many degrees and how quickly the turn will occur.

==See also==
* [[Smooth Turn]]

[[Category:Terms]]

Snap Turn

2019-01-05T19:36:38Z

Jason VR: add term

A '''Snap Turn''', also sometimes referred to as '''Click Turn''', '''Incremental Turn''', '''Blink Turn''', is a movement style some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user attempts to turn their character through the use of a button or some other control, their character will "instantly" turn by a pre-determined amount. Often a value like 15 degrees, 30, 45, or 90 degrees.

The turn may happen with an instant view shift, or the view may turn gradually but extremely quickly (to avoid motion sickness), or [[Vignetting]] may be used.

In some VR content, this is a feature that can be turned on or off, or adjusted as to how many degrees and how quickly the turn will occur.

==See also==
* [[Smooth Turn]]

[[Category:Terms]]

VCS

2019-01-05T19:19:17Z

Jason VR: Create redirect

#REDIRECT [[Interpupillary_distance#Virtual_IPD]]

ICD

2019-01-05T19:18:26Z

Jason VR: Create redirect

#REDIRECT [[Interpupillary_distance#Virtual_IPD]]

Interpupillary distance

2019-01-05T19:17:14Z

Jason VR: /* Virtual IPD */ mention ICD, VCS

'''Interpupillary distance''' or '''IPD''' is the distance between the pupils of your eyes. There are two types of IPDs: [[#Real IPD|Real IPD]] and [[#Virtual IPD|Virtual IPD]].

==Real IPD==
Real IPD is the actual distance between the center of your eyes' pupils in real life. Any [[Head-mounted Display]] require this measurement to accurately position the virtual camera outputs on the screen in front of the user's eyes. The outputs have to be directly in front of both of the users' eyes. Any deviation can cause [[eye strain]]. Most [[HMD]]s allow users to adjust their camera output positions to match their IPD.

The average IPD for humans is 64 millimeter, with a range of 54 to 72 millimeter. You can measure your IPD by measuring the distance between the center of your pupils with a ruler.
==Virtual IPD==
Virtual IPD, sometimes referred to as ICD (Inter Camera Distance) or VCS (Virtual Camera Separation), is the distance between the 2 virtual eyes (cameras) in [[Virtual Reality]]. This number can change the [[Sense of Scale]] of the objects in the virtual environment in relation to the user.

Developers can change the sense of scale by changing virtual IPD. They can cause the environment to increase or decrease in size by changing the virtual IPD.

[[Category:Terms]]

Snap Turn

2019-01-05T18:58:27Z

Jason VR: add See Also

A '''Snap Turn''', also sometimes referred to as '''Click Turn''' or '''Blink Turn''', is a movement style some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user attempts to turn their character through the use of a button or some other control, their character will "instantly" turn by a pre-determined amount. Often a value like 15 degrees, 30, 45, or 90 degrees.

The turn may happen with an instant view shift, or the view may turn gradually but extremely quickly (to avoid motion sickness), or [[Vignetting]] may be used.

In some VR content, this is a feature that can be turned on or off, or adjusted as to how many degrees and how quickly the turn will occur.

==See also==
* [[Smooth Turn]]

[[Category:Terms]]

Smooth Turn

2019-01-05T18:57:41Z

Jason VR: Create page

A '''Smooth Turn''', also sometimes referred to as '''Continuous Turn''', is a movement style some VR creators offer in their VR content. When the user attempts to turn their character through the use of a button or some other control, their character's view gradually shifts in the desired direction. [[Vignetting]] may be used.

In some VR content, this is a feature that can be turned on or off, or adjusted as to how quickly the turn will occur. A high-speed turn can reduce the chance of motion sickness

==See also==
* [[Snap Turn]]

[[Category:Terms]]

Snap Turn

2019-01-05T18:54:49Z

Jason VR: word choices

Snap Turn

2019-01-05T18:53:54Z

Jason VR: formatting

A '''Snap Turn''', also sometimes referred to as '''Click Turn''' or '''Blink Turn''', is a movement style some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user attempts to turn their character through the use of a button or some other control, their character will "instantly" turn by a pre-determined amount. Often a value like 15 degrees, 30, 45, or 90.

The turn may happen with an instant view shift, or the view may turn gradually but extremely quickly (to avoid motion sickness), or [[Vignetting]] may be used.

In some VR content, this is a feature that can be turned on or off, or adjusted as to how many degrees and how quickly the turn will occur.

[[Category:Terms]]

Snap Turn

2019-01-05T18:53:34Z

Jason VR: Create page

A '''Snap Turn''', also sometimes referred to as '''Click Turn''' or ''Blink Turn'', is a movement style some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user attempts to turn their character through the use of a button or some other control, their character will "instantly" turn by a pre-determined amount. Often a value like 15 degrees, 30, 45, or 90.

The turn may happen with an instant view shift, or the view may turn gradually but extremely quickly (to avoid motion sickness), or [[Vignetting]] may be used.

In some VR content, this is a feature that can be turned on or off, or adjusted as to how many degrees and how quickly the turn will occur.

[[Category:Terms]]

Dynamic FOV Reduction

2019-01-05T18:43:35Z

Jason VR: add Reference

'''Dynamic FOV Reduction''', also sometimes referred to as '''Blinders''', '''Blinkers''', or '''Vignetting''', is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, driving, etc, their [[Field of view|FOV]] is automatically temporarily reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

In some VR content, this is a feature that can be turned on or off, or adjusted as to when or how often it will occur, and how significantly the [[FOV]] will be altered. Setting a FOV Reduction setting to a "strong" setting would mean that the user's FOV is significantly reduced when the reduction is triggered.

==References==
* Ajoy S Fernandes and Steven K. Feiner, [http://www.cs.columbia.edu/2016/combating-vr-sickness/images/combating-vr-sickness.pdf Combating VR Sickness through Subtle Dynamic Field-Of-View Modification]; IEEE Symposium on 3D User Interfaces 2016

[[Category:Terms]]

Vignetting

2019-01-05T18:39:28Z

Jason VR: fix redirect

#REDIRECT [[Dynamic FOV Reduction]]

Blinders

2019-01-05T18:39:00Z

Jason VR: fix redirect

#REDIRECT [[Dynamic FOV Reduction]]

Dynamic FOV Reduction

2019-01-05T18:38:01Z

Jason VR: formatting

FOV Reduction

2019-01-05T18:37:29Z

Jason VR: Jason VR moved page FOV Reduction to Dynamic FOV Reduction: Correcting terminology

#REDIRECT [[Dynamic FOV Reduction]]

Dynamic FOV Reduction

2019-01-05T18:37:29Z

Jason VR: Jason VR moved page FOV Reduction to Dynamic FOV Reduction: Correcting terminology

[[FOV Reduction]], also sometimes referred to as '''Blinders''', '''Blinkers''', or '''Vignetting''', is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, driving, etc, their [[Field of view|FOV]] is automatically temporarily reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

In some VR content, this is a feature that can be turned on or off, or adjusted as to when or how often it will occur, and how significantly the [[FOV]] will be altered. Setting a FOV Reduction setting to a "strong" setting would mean that the user's FOV is significantly reduced when the reduction is triggered.

[[Category:Terms]]

Dynamic FOV Reduction

2019-01-05T16:44:00Z

Jason VR: word choices

Dynamic FOV Reduction

2019-01-05T16:43:22Z

Jason VR: word choices

[[FOV Reduction]], also sometimes referred to as '''Blinders''', '''Blinkers''', or '''Vignetting''', is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, driving, etc, their [[Field of view|FOV]] is automatically temporarily reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

In some VR content, this is a feature that can be turned on or off, or adjusted when or how often it occurs, and how significantly the [[FOV]] is altered. Setting a FOV Reduction setting to a "strong" setting would mean that the user's FOV is significantly reduced when the reduction is triggered.

[[Category:Terms]]

Dynamic FOV Reduction

2019-01-05T16:41:59Z

Jason VR: add driving

[[FOV Reduction]], also sometimes referred to as '''Blinders''', '''Blinkers''', or '''Vignetting''', is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, driving, etc, their [[Field of view|FOV]] is automatically temporarily reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

In some VR content, this is a feature that can be turned on or off, or adjusted when or how often it occurs, and how significantly the [[FOV]] is altered. Setting a FOV Reduction setting to a "strong" setting would mean that the user's FOV is greatly reduced when it happens.

[[Category:Terms]]

Vignetting

2019-01-05T16:41:20Z

Jason VR: Create redirect

#REDIRECT [[FOV Reduction]]

Blinders

2019-01-05T16:40:41Z

Jason VR: Create redirect

#REDIRECT [[FOV Reduction]]

Dynamic FOV Reduction

2019-01-05T16:38:52Z

Jason VR: formatting

[[FOV Reduction]], also sometimes referred to as '''Blinders''', '''Blinkers''', or '''Vignetting''', is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, flying, etc, their [[Field of view|FOV]] is automatically temporarily reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

In some VR content, this is a feature that can be turned on or off, or adjusted when or how often it occurs, and how significantly the [[FOV]] is altered. Setting a FOV Reduction setting to a "strong" setting would mean that the user's FOV is greatly reduced when it happens.

[[Category:Terms]]

Dynamic FOV Reduction

2019-01-05T16:38:04Z

Jason VR: formatting

[[FOV Reduction]], also sometimes referred to as '''Blinders''', '''Blinkers''', or '''Vignetting''', is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, flying, etc, their [[#Field of view|FOV]] is automatically temporarily reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

In some VR content, this is a feature that can be turned on or off, or adjusted when or how often it occurs, and how significantly the FOV is altered. Setting a FOV Reduction setting to a "strong" setting would mean that the user's FOV is greatly reduced when it happens.

[[Category:Terms]]

Dynamic FOV Reduction

2019-01-05T16:35:11Z

Jason VR: describe configurability

[[FOV Reduction]], also sometimes referred to as '''Blinders''', '''Blinkers''', or '''Vignetting''', is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, flying, etc, their [[FOV]] is automatically temporarily reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

In some VR content, this is a feature that can be turned on or off, or adjusted when or how often it occurs, and how significantly the FOV is altered. Setting a FOV Reduction setting to a "strong" setting would mean that the user's FOV is greatly reduced when it happens.

[[Category:Terms]]

Dynamic FOV Reduction

2019-01-05T16:33:01Z

Jason VR: small edits

Dynamic FOV Reduction

2019-01-05T16:29:12Z

Jason VR: Create page

[[FOV Reduction]], also sometimes referred to as Blinders, Blinkers, or Vignetting, is a user interface feature some VR creators offer in their VR content. In an effort to reduce potential motion sickness, when the user performs certain in-game motion actions, such as turning, running, jumping, falling, flying, etc, their FOV is automatically reduced. This may help reduce or prevent motion sickness.

The user's view might be restricted to a small circle, or have black borders on the left and right, or the screen may be briefly blacked-out entirely.

[[Category:Terms]]