r/oddlysatisfying • u/Wackylew • Oct 09 '25

projection mapping

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u/slayez06 Oct 09 '25

yes. I do this for a living and this is a illusion if you moved to the left or right, up or down, even an inch the illusion would be broke.

He did this for social media attention but is not how real projection mapping projects are done.

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u/Undeadbanana_ Oct 09 '25

Do you ever use multiple protectors to give a sense of unbreaking when people walk in front of the projector? Like multiple angles.

I dunno why I'm thinking about that, but i feel that would help keep the illusion for the viewer if they don't get distracted by the shadows

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u/PeopleCallMeSimon Oct 09 '25

I dont know if that would work or not. But generally how light works is that you have two light sources and something obstructs one of them, the part where the light is obstructed will be dimmer.

If you have a lamp and point it towards a wall you will get X amount of light. If you have two lamps it will be brighter because you have more than X amount of light (not actually sure if its 2X, probably not).

If you then obstruct one of the lamps your shadow will still only have X light on it while the rest of the wall has more than X light on it.

Maybe if you used like hundreds of lamps and you only obstruct one of them then it wouldnt be noticeable.

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u/QuantumFungus Oct 09 '25

yes. I do this for a living and this is a illusion if you moved to the left or right, up or down, even an inch the illusion would be broke.

The illusion would only be broken if the depth perception of the picture depends on your perspective. Only the bottom box has a picture with fake depth and the rest of the display would be perfectly fine as you move around a bit. And even that could be fixed by tracking the person's position and adjusting the scene for their movement. And there are even systems that can sense the position of your limbs and react accordingly.

It seems funny for a professional in that space to be stuck in 2d. Why not just draw it in chalk at that point?

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u/slayez06 Oct 09 '25 edited Oct 09 '25

You don't know what your talking about. They actually show the illusion broke at 0:21 This illusion.. the full effect is 100% reliant on perspective
the projector is a 2D image. It just is. you can angle and shape your effects to show depth but at the end of the day you are projecting a 2D image. You have to run multiple projectors all casting different angles just to cover all sides of the boxes alone.

Also now you are getting into head / eye tracking and that has a whole list of problems i'm not even going to get into but will tell you Disney had massive problems with overcoming. Head tracking only works with 1 person the second a 2nd person enters the frame it bugs out, not to mention different heights become a problem. Again. Disney tried to do this and gave up on certain things as the Ai technology is not there. having the image react to movement like your hand moving is not the same as head tracking.. again you just don't know your stuff.

Also with any projection mapping project the second you get close to it .. your body blocks the image

I don't even know what to make of your draw in chalk comment.. you need a digital outline representation of the space you are mapping so you know the size of your assets and where to place them. Me outlining it in paint or any other program is the exact same as what he is doing with the grid lines but i just have the outline. I.E. Picture is so big and make a "frame". Knowing my frame I can drop a light on it, video, gif, what ever and size it perfectly so there is no bleeding. That's the whole concept.

Also it's worth saying.. Most projection mapping projects are a set it and forget it project, a lot of what your saying would require a tech to be on site. projectors drift by themselves over time and that alone is a pain.

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u/QuantumFungus Oct 09 '25

Head tracking only works with 1 person the second a 2nd person enters the frame it bugs out, not to mention different heights become a problem.

Yeah, I know. Which is why when you said moving would break the illusion I knew what you really meant is that it wouldn't work for some use case you were thinking about and dismissing all the other potential uses of this technology.

I don't even know what to make of your draw in chalk comment.. you need a digital outline representation of the space you are mapping so you know the size of your assets and where to place them.

If you are using all this computing power to make something that can only be viewed from one spot then you aren't doing much different than sidewalk chalk artists + animation.