Half Dome

Half Dome
Basic Info
VR/AR	Virtual reality
Type	Head-mounted display
Developer	Reality Labs (as Oculus Research, later Facebook Reality Labs)
Announcement Date	2 May 2018 (Half Dome, shown at F8 2018)
Release Date	Not released; internal research prototypes
Versions	Half Dome Zero (2017), Half Dome or Half Dome 1 (2018), Half Dome 2 (2019), Half Dome 3 (2019)
Display
Display	Varifocal (mechanical in Half Dome 1 and 2; electronic in Half Dome 3)
Image
Field of View	140 degrees (Half Dome 1)
Optics
Optics	Fresnel lenses (Half Dome 1); folded optical path (Half Dome 2); stack of six liquid crystal lenses with 64 focal planes (Half Dome 3)
Tracking
Eye Tracking	Yes
Device
Weight	680 g (Half Dome Zero); Half Dome 2 is 200 g lighter than Half Dome 1

Half Dome is a series of varifocal virtual reality headset prototypes built by the research group of Oculus VR and Facebook (now Meta Platforms), known at different times as Oculus Research, Facebook Reality Labs and Reality Labs Research. The headsets use eye tracking to find where the wearer is looking and change the focal distance of the displays to match, an approach meant to reduce the vergence-accommodation conflict of fixed-focus headsets.

The program was led by Douglas Lanman. Meta has identified four headsets in the series: Half Dome Zero (2017), Half Dome 1 (first shown at F8 in May 2018), and Half Dome 2 and Half Dome 3, both presented by Michael Abrash at Oculus Connect 6 in September 2019. None of them was sold. In 2018 an Oculus spokesperson told UploadVR, "We may never see these specific technologies in a product."

Reviewed 15 October 2026. All dates, quotes, names, roles, weights, field-of-view and lens figures checked against the cited Meta blog posts, Meta research page, Crossref record for the DeepFocus paper, and the Engadget, Road to VR and UploadVR articles. About review dates.

Background

Most consumer headsets present all virtual content at a single fixed focal distance. In a May 2018 interview with UploadVR, Lanman said most of them "just lock the optical focus of the displays to something around two meters." The eyes still converge at the depth of a virtual object, but they focus at that fixed distance. Lanman said this sustained vergence-accommodation conflict "has been linked, in prior vision science publications, to visual fatigue, including eye strain." A varifocal display addresses the problem by moving the focal distance to whatever depth the user is looking at.

Lanman joined Oculus Research in June 2014. According to Meta, the team spent about a year choosing a problem, considering resolution, dynamic range and compact form factors before settling on the vergence-accommodation conflict. In a 2023 interview published by Meta, Lanman said the team first learned about varifocal displays from papers written in the 1990s and "first started working on it ourselves in 2015."

Development

Early prototypes

Lanman pitched the project together with mechanical engineering lead Ryan Ebert, and within a couple of months Lanman, Ebert and lead computer vision scientist Alex Fix had a first working prototype. Meta's 2018 account describes three stages: a basic proof of concept for varifocal displays, a second prototype about a year later that added eye tracking, and a third that roughly matched the size, weight and field of view of other VR headsets of the time. UploadVR, reporting on Lanman's 2018 talk, wrote that the moving-display system "started with a loud monstrosity" before it was engineered into Half Dome.

A 2016 demo of Half Dome produced real-time defocus blur through accumulation buffer rendering, in which the scene was rendered 32 times per eye. Meta says this was possible only because the demo scene was simple.

Meta credits about 40 people across Oculus and Facebook with the 2018 headset. Besides Lanman, Ebert and Fix, they included eye tracking research lead Robert Cavin, research scientist Marina Zannoli (requirements and perception), technical program manager Kim Corson, and optical scientist Brian Wheelwright, who worked on the moving varifocal screens. UploadVR also credited wide field of view optics to a team led by Jacques Gollier.

Half Dome Zero (2017)

Half Dome Zero was a 680-gram research headset that Meta says was fully compatible with every VR game then shipping for the Oculus Rift. For comparison, Meta gives the Rift's weight as 470 grams. To build it, the team had to cut mass by a factor of four relative to its existing 2,450-gram research headset.

Half Dome Zero was used in a 2017 user study led by Zannoli, then a vision scientist on the team. Sixty-three participants completed a two-day trial, using varifocal on one day and fixed focus on the other, with 30 minutes in VR spread across three experiences. According to Zannoli, quoted by Meta, participants using varifocal experienced less fatigue, nausea and blurry vision, identified small objects better, read text more easily and reacted more quickly to their visual environment; Meta says most participants preferred varifocal over fixed focus. An error in the study had switched off lens distortion correction for varifocal, and the team concluded that varifocal showed significant benefits only when distortion correction was applied correctly.

Half Dome 1 (2018)

Maria Fernandez Guajardo, head of product management for Oculus Core Tech, showed Half Dome near the end of the second day of Facebook's F8 developer conference, on 2 May 2018. It had a 140-degree field of view, compared with 110 degrees for the Rift. Meta later described it as combining mechanical varifocal displays with a wider field of view than the original Rift, using Fresnel lenses, and physically moving the screens based on eye tracking. Some press reports at the time described the moving parts as the lenses instead. Fernandez Guajardo said continued work on lenses had let Oculus "pack all of this technology and still keep the Rift form-factor."

Later that month Lanman gave the opening keynote at Display Week in Los Angeles. In an interview with UploadVR he said, "In a quiet room I don't hear the screens or feel them moving," and described the headsets as "still feature prototypes, so the engineering isn't completely perfected." Wheelwright said the core of the Half Dome hardware was optomechanics rather than optics, since the lenses had to work with the moving screens across the whole varifocal range while keeping a wide field of view. Cavin described working with the optics group on new ways of folding light so the eye could be imaged "without obstructing the screen movement."

Oculus co-founder Nate Mitchell said after F8 that people should not "expect to see all of these technologies in a product anytime soon," calling the demo "just a peek into some feature prototypes."

Half Dome 2 and Half Dome 3 (2019)

At Oculus Connect 6 on 25 September 2019, Abrash presented two further prototypes built by the Display Systems Research team. Meta described the original Half Dome as "a proof of concept that prioritized visual immersion"; the new headsets were aimed at comfort for long sessions, including virtual work.

Half Dome 2 kept a mechanical varifocal design. Its optical path was folded into a much smaller volume, and it was 200 grams lighter than Half Dome 1. It replaced the original mechanical actuators with voice coil actuators and flexure hinge arrays, which Meta said reduce friction, minimize noise and extend the life of the moving parts. Its field of view was narrower than Half Dome 1 but about 20 percent wider than Oculus Quest. Road to VR reported that the voice coil actuator reduced sound and vibration from the varifocal mechanism to "imperceptible" levels.

Half Dome 3 had no moving parts. Its electronic varifocal system used liquid crystal lenses built from alternating polarization-dependent lenses and switchable half-wave plates. Each additional pair of lenses doubles the number of focal planes, and in the demo module six liquid crystal lenses switched through 64 focal planes, so many that, according to Meta, the result appears continuous. Meta said that the electronic varifocal system was smaller than the mechanical system of the original Half Dome, and called the work "still very much research." Abrash said both new prototypes still had a wider field of view than the Rift and Quest headsets of the time.

Half Dome prototypes

Prototype	Shown	Focus mechanism	Reported details
Half Dome Zero	Used in a 2017 study	Varifocal	680 g; compatible with Rift games; used in a 63-person user study
Half Dome 1	F8, 2 May 2018	Mechanical, moving screens driven by eye tracking	140-degree field of view; Fresnel lenses
Half Dome 2	Oculus Connect 6, 25 September 2019	Mechanical, voice coil actuators and flexure hinges	200 g lighter than Half Dome 1; folded optics; field of view about 20 percent wider than Oculus Quest
Half Dome 3	Oculus Connect 6, 25 September 2019	Electronic, liquid crystal lens stack	Six liquid crystal lenses, 64 focal planes; no moving parts

Rendering

A varifocal display keeps the fixated depth sharp, but objects at other depths also need realistic blur. In December 2018 Facebook Reality Labs introduced DeepFocus, a neural network rendering system for Half Dome that produces gaze-contingent defocus blur in real time from the color and depth (RGB-D) images that most game engines already generate. Lanman said, "I wanted something that could work with every single game immediately." Meta released the code and training data set as open source. The accompanying paper, "DeepFocus: Learned Image Synthesis for Computational Displays" by Lei Xiao, Anton Kaplanyan, Alexander Fix, Matthew Chapman and Douglas Lanman, was presented at SIGGRAPH Asia 2018 and published in ACM Transactions on Graphics. It describes a single convolutional network that can generate defocus blur, focal stacks, multilayer decompositions and multiview imagery for varifocal, multifocal and light field displays.

Reception and assessment

In Road to VR's report on the F8 reveal, Scott Hayden noted that physically moving displays add moving parts that could complicate manufacturing, raise cost and affect durability. In 2020 UploadVR described constant mechanical movement as a potential "reliability nightmare waiting to happen," in contrast with Half Dome 3, which has no moving parts.

In a keynote at the SPIE AR VR MR conference in 2020, Lanman rated the series on NASA's nine-level technology readiness scale. He placed the mechanical Half Dome at level 6 ("Prototype System") and Half Dome 3 at level 5 ("Large Scale Prototype"), and said Half Dome 3 was "almost ready for primetime." According to UploadVR, he said his team usually works at levels 2 to 4.

Later work

In 2022 Meta described Mirror Lake, a concept headset design into which "the slim electronic varifocal modules from Half Dome 3 can be added to resolve vergence-accommodation conflict." Meta called Mirror Lake only a concept.

At SIGGRAPH 2023 the Display Systems Research team showed Butterscotch Varifocal, which used the mechanical varifocal mechanism of Half Dome 1 and 2 together with a retinal-resolution display of about 60 pixels per degree and a 50-degree field of view. Lanman called it the "greatest hits" of the Half Dome and Butterscotch series, but explained that it was not named Half Dome 4 because, unlike past Half Dome headsets, it was "solely focused on showcasing the experience of retinal resolution in VR," not necessarily with hardware suitable for consumers. Meta wrote at the time that "Our work on Half Dome prototypes continues."

See also

• Varifocal display
• Vergence-accommodation conflict
• Douglas Lanman
• Reality Labs
• Focal surface display