Passthrough
Passthrough is the headset function that shows the physical surroundings live through the headset's cameras, so the wearer can see the room without taking the headset off (Meta). The augmented reality literature calls this design video see-through, to set it apart from optical see-through headsets, in which the wearer looks through partially transparent combiners (Azuma, 1997).
Fyware's XR glossary, with the source behind each definition.
Passthrough is the headset function that shows the physical surroundings live through the headset's cameras, so the wearer can see the room without taking the headset off (Meta). The augmented reality literature calls this design video see-through, to set it apart from optical see-through headsets, in which the wearer looks through partially transparent combiners (Azuma, 1997).
On a plant floor, passthrough serves safety first. Meta's health and safety warnings say it helps the wearer stay inside the activity space and alerts them when they approach or cross the safety boundary during fully immersive use, and they tell users to stop or check their surroundings with passthrough whenever they are unsure the area is safe. The same warnings note that the headset limits the field of view, so the wearer may not perceive something at their side, above or below them; even with passthrough on, a station needs a cleared area away from moving equipment. Passthrough also lets someone answer a coworker or glance at a panel without removing the headset, and on the Quest 3 a double tap on either side switches it on or off once that option is enabled. It is, finally, the basis of mixed reality: once the headset recognizes the floor and the surfaces of the room, it can place digital objects there, next to the person's workstation.
Ronald Azuma compared the two ways of mixing the physical and the virtual in front of the eyes in his 1997 survey of augmented reality. In an optical see-through headset, of which HoloLens is a later example, partially transmissive combiners let the light of the room through and reflect the digital image on top. In a video see-through headset, such as the Meta Quest 3, the headset is closed: one or two cameras capture the surroundings, and the system blends them with the digital content before showing them on the displays. Meta's design guidelines add that passthrough has to reproduce depth and correct distortion, because a simple single-viewpoint video conveys no depth and can be uncomfortable or unsafe.
Video gives more freedom to combine: each pixel can come from the room, from the virtual scene or from a blend of both, so a digital object can hide a physical one. In exchange, everything the person sees of the room passes through cameras and displays, and that explains the specs worth checking. Meta lists full-color passthrough at 4 megapixels and 18 pixels per degree for the Quest 3 and 3S, below the 25 pixels per degree at which the Quest 3 displays virtual content, so a small label is harder to read through the cameras than with the naked eye. Light matters as well. Meta recommends at least 50 lux for color passthrough, roughly the soft evening light of a family room, and proposes a book test: if you can read comfortably in the room, there is probably enough light. Delay is the last cost. Azuma noted that the camera stream and the virtual stream each carry delays in the tens of milliseconds and have to stay synchronized, or the image distorts in time; and if the power fails, he wrote, the wearer of a video headset is effectively blind, while an optical headset turns into a pair of heavy sunglasses.
Outside headsets, the word means other things. In audio and networking it describes a device that lets a signal or traffic through without processing it, and in US tax law a pass-through entity is a business whose profits are taxed on its owners' returns. This entry covers only the headset.
The mixed reality extinguisher station at Fyware's Safety Week runs on passthrough: Fyware's technicians scan the room and place the fire on top of it, so the person keeps seeing their own plant while identifying the fire class and choosing the extinguisher. The fire extinguisher simulator in Fyware Safe works the same way. The headset scans the room and places two to five fire sources, each with its class, along with the extinguisher cart and the exit door, on that same floor, in a clear area of 2 by 2 meters (about 6.5 by 6.5 feet). Since everything the person sees of the room arrives through the cameras, the station goes in a well-lit spot.
«step outside your immersive view to see a real-time view of your surroundings»
Meta defines passthrough as the feature that lets the wearer step outside the immersive view to see the surroundings live, and recommends at least 50 lux for full-color passthrough.
Source: Meta Quest Help Center, “How to use Passthrough on Meta Quest”, accessed October 23, 2026
«combining a closed-view HMD with one or two head-mounted video cameras»
Azuma compares optical and video see-through headsets: in the video design, cameras provide the view of the surroundings, resolution is limited by the display and a power cut leaves the user unable to see.
«Full color passthrough (4MP, 18 PPD)»
Meta lists full-color passthrough at 4 megapixels and 18 pixels per degree for the Quest 3 and the Quest 3S, and 25 pixels per degree for the Quest 3 display.
Source: Meta, “Compare Meta Quest”, Quest 3S vs. Quest 3 table, accessed October 23, 2026
«Depending on the device model, passthrough may be displayed in color or grayscale.»
Meta's design guidelines describe passthrough as a video feed from the headset's cameras that has to provide depth and proper distortion, shown in color or in grayscale depending on the model.
From the menu: press the Meta button on the right controller to open the Navigator, select Quick settings in the System bar and then Passthrough. On the Quest 3 you can also turn on Double Tap for Passthrough in the passthrough settings, and from then on two taps on either side of the headset switch it on or off. On the Quest 3S, the action button at the bottom right of the headset does the same.
Yes, in grayscale. Meta's design guidelines use the Quest 2's grayscale passthrough as their example, and its help center lists the Quest 2 among the headsets that can toggle passthrough with a double tap. Full-color passthrough comes with the Quest 3, the Quest 3S and the Quest Pro, and for the 3 and the 3S Meta publishes 4 megapixels and 18 pixels per degree.
With passthrough, the headset is closed and the wearer sees the room through cameras and displays, so the system can replace or hide any part of the view. With optical see-through, as in HoloLens, the wearer looks at the room through partially transparent combiners and the digital image is reflected on top. Azuma's 1997 survey lists the trade-offs: video limits what is seen of the room to the resolution of the display and blinds the wearer if the power fails, while optical keeps the direct view.
Tell us what you want to solve in your plant. Fyware designs extended reality around the equipment and constraints of your operation, and builds it to grow from a pilot to the whole site.
Tom Klukowski, Fyware Partner · Valcre Marketing We reply in under 24 business hours, with scope, timeline and investment range.In the meeting you see the simulator running and what it would take to bring it to your plant, with scenarios adapted to your layout. And if you need to sell it internally, this page is your presentation: share it with your team.
