Is it possible to make a layer illuminate another layer like a light?

[A.I.1]

I have layers that are compositions where I'm using the stroke effect and the glow effect - so it looks like it's some sort of lighting (like flurescent light or something).

So I've placed qutie a few layers of those compositions as layers in a new composition in 3d space, as though they are stood up. I've also created a long floor flat solid that goes under them.

Is there a simple way of making those layers illuminate the floor with whatever colour of "lights"  are in the layer (ie. what was   just done with the stroke and glow effects)? Like a reflection of the lighting on the floor.

I know some tutorials suggest to duplicate a copy of the layer and rotate/flip it so it's on the floor but that's not going to be that accurate (and it should really be lighting up the front, back and sides of the part of the floor where that layer is).

Also the 3d camera will be moving forward in 3D space so what might look okay for a static scene (eg. just creating a flipped version of a layer for a reflection) may not work as well when the camera is moving forward. Also in the precomp the stroke effect is moving - so that would complicate things if trying to add the reflections using real after effects lights.

edit: I've attahed an image to show what I mean. I've added some real After Effects lights but I really want it to seem like the layer (precomp that's made with the stroke and glow effects) is lighting up the floor.

[Mylenium · Accepted solution]

No. Emissive surfaces require a full 3D raytracing solution that supports it and it's neither technically trivial nor in any way performance friendly. You're literally talking stuff where even 3D renderers with GPU acceleration can chew on a single frame for minutes or even hours to calculate the path tracing. It's a far cry from being anything that can be implemented into a compositing app in an intuitive manner and with adequate realtimeness. Even games with RTX support mostly fake it still or limit it to a handful of light sources/ surfaces. Maybe in another twenty years...

Mylenium

[A.I.1]

Okay thanks a lot. I'll continue trying to fake it (eg. with rotating a copy of the layer so it's on the floor and blurring it, but that won't be as accurate as it would be if it could do it for real - and it will only be at the front, and maybe I'll add some more after effects lights).

There's stock clips (and a .ppt premiere pro template - though I don't have premiere pro) that have a "neon tunnel" effect where some seem to be reflecting the neon lights on the floor. Maybe they're mostly faked or made with proper 3d software. Though I don't want to use a stock clip for this project and want it more custom. So I'll try to fake it. Thanks.

[Rick Gerard]

You can put a layer in front of a light and set the layer to cast shadows only and set the light transmission to 100%. This will give you a projector, but you can't use blend modes or other effects to change the appearance of the projection. Maybe this will give you some ideas. 

[A.I.1]

Thanks. So I set a point light (radius 1000, intensity 100%) behind a precomp layer and set the precomp layer to "casts shadows only" and light transmision 100%. That then doesn't show the layer so I added the precomp layer normally in front of it. I set the light layer to white so then it seems to only light the floor with the white light.If there are multiple colorus in the precomp layer (for different coloured neon lights, created using stroke and glow effects) it doesn't create the multi-colored light effects reflected on the floor with this projection method. Ideally we'd see the different colours of the moving effects from the precomp being reflected on the floor layer.