Not getting camera projection on light texture

[glacierise]

Hi guys,

We need to camera project a texture to use in the a vray light's texture slot. We tried a couple things with no success:

- set the map to environment/screen mapping mode
- use the camera map per pixel map

Any ideas on how to get that working?
Thanks

[glacierise]

It's a showstopper problem for us on this project, would be great to know if that's something that can be fixed. Thanks!

[tashko.zashev]

Hi,

The Camera map per pixel seems to have quite limited functionality and I don't think it can be used in this scenario. I tried several approaches including Scanline and max lights setup but it doesn't work.
Maybe it would be possible to get what you want using Camera map per pixel in conjunction with a V-Ray light material or a regular material with mapped Self illumination slot ?

[glacierise]

Thanks for getting onto this! Self illuminated won't really help, because we're illuminating environment fog, and the render times would become prohibitive. Even without camera map per pixel, using a map in environment/screen mapping mode should work, and it's not - looks like the light doesn't respect this type of mapping. It would be great if we had control on the UVs the light is using - maybe pick them up from an object or something?
Thanks

[tashko.zashev]

Can you give us an example setup so we can investigate further relying on your specific scenario ?

[glacierise]

Here' s a scene:

https://www.dropbox.com/s/x7t18qog56...018_4.max?dl=0

V-Ray 3.60.03, Max 2018.4

You can see how the light is not using the environment/screen UVs.

Fixing that would be great, hotfix would be awesome. Giving us control over the UVs would be even better, for the longer term.

Tried in VRay RT CPU - the bug is not there, the light does respect the env/screen UVs. But it is not illuminating environment fog when texture is on, so we can't use it Not sure if that's a bug or a limitation.

Thanks

[Morne]

Have you guys tried this?
http://www.rensheeren.com/blog/osl-cammapscale/

[glacierise]

Hi Morne,

Yeah that's not working either - it's not a problem with the camera map per pixel but the light not getting the UVs correctly it seems.

Thanks

[tashko.zashev]

Here' s a scene:

https://www.dropbox.com/s/x7t18qog56...018_4.max?dl=0

V-Ray 3.60.03, Max 2018.4

You can see how the light is not using the environment/screen UVs.

Fixing that would be great, hotfix would be awesome. Giving us control over the UVs would be even better, for the longer term.

Tried in VRay RT CPU - the bug is not there, the light does respect the env/screen UVs. But it is not illuminating environment fog when texture is on, so we can't use it Not sure if that's a bug or a limitation.

Thanks

It does sound like a bug that we can fix, I'll forward the case to our developers and will keep you posted for any news.

[glacierise]

Great, thanks!

[Art48]

Have you tried placing a plane at the appropriate location, map the texture onto said plane, then render-to-texture and use the resulting texture as the texture for the light?

[vlado]

Unfortunately this is not at all easy to implement. Will see what can be done about it, but for the moment, the workaround suggested by Art48 with baking the texture should work.

Best regards,
Vlado

[glacierise]

Ok, we'll try this out, thanks. Cool workaround, should have thought about it