Snap Specs Lens 如何展示輪椅使用者看到的展廳眩光位置
I built a Snap Specs Lens that shows where gallery glare lands for wheelchair users
作者為 Devpost 的 Learn AR with SPECS hackathon 製作 Snap Specs Lens，展示不同眼睛高度下，展廳射燈在畫框玻璃上形成的眩光區域。兩盞燈移至距牆 62 cm 後，三種示例高度的眩光區域都避開觀賞區；但眼睛高度設為 96 cm 時，眩光仍會進入觀賞區。工具目前只在 Lens Studio 預覽中運行，尚未在 Specs 硬件上測試。
Most gallery lights get hung where the usual aiming rule puts them, and that rule has one person in it: a standing adult with eyes about 160 cm up. From a wheelchair your eyes are a lot lower, and the same light can put its glare right on the glass over the art.
The Smithsonian's accessibility guidelines say it plainly: "The elimination of glare from cases and on labels must be considered for those visitors who are seated as well as for those who are standing." About 5.5 million US adults used a wheelchair in 2014. I couldn't find a tool that shows all of those eye heights at once, so for Devpost's Learn AR with SPECS hackathon I made one.
What it does
Glare Zone puts a practice wall, a framed print and two track lights in front of you. On the floor it draws where each light's reflection in the glass can be seen, for three eye heights: standing, seated in a wheelchair, and a child in a wheelchair.
With the lights where the usual rule puts them, the seated zone reaches 73.5 cm out from the wall, past the start of the viewing area. Slide both lights in to 62 cm and all three zones clear. The card only says "All three: clear" when that's true for all three heights.
Those three heights are examples, though. Set "My eyes" to 96 cm, the low end of a UK guide's range for wheelchair users, and the glare zone reaches the viewing area again. The card estimates that at 62 cm about 20% of wheelchair users would still see glare.
And fixing glare isn't free. Moving the lights in makes the beam steeper, from 58 to 62 degrees, and the Lens turns that label amber past 60, because a steeper beam can bring out texture on the art. I'd rather show that trade-off than hide it.
Why glasses
You have to stand where the glare is to see it. The zones are drawn on the floor at real size, so you can walk into one and look up at the glass from that height, and your hands stay free to move the light.
How I built it
I planned it with the Devpost Learn skill pack first. The plan-lens interview turned my answers into a design brief with five done criteria.
Then CLAD built and tested it in Lens Studio through the Lens Studio MCP, across 42 sessions on my Windows PC. CLAD's skills did parts of it too: specs-world-query to place the wall on a real surface, and build-sfx for the soft sound when the card turns clear. 28 LEAF scenarios test it in the preview, and 55 unit tests run on every push.
The lamp numbers come from a real fixture's published data sheet, the TSLight RXT13, not made-up sample values.
What I learned
The usual aiming rule only has one eye in it. When I worked through the geometry, a light 65 cm out still put the child's glare in the viewing area, so the demo moved to 62.
Limits
Everything in the video runs in the Lens Studio preview. It hasn't run on Specs hardware yet. The glare is computed from the geometry, not measured with a light meter, and the wheelchair numbers are estimates from two published percentiles. It doesn't replace asking real visitors, so next I want it in front of the people who light real shows, and people who use wheelchairs.
來源：DEV Community · dev.to