PDA

View Full Version : Volumetric lights and occlusion problem



Slartibartfast
02-19-2014, 10:34 AM
Hi!

I have problems with a render in wich a volumetric spotlight is shining onto a Surface with a nodal occlusion shader. The lit areas is not showing any textures, just gray tones. I tried both native and DPKit shaders, but same result. Now, there is a workaround - using occlusion pass in image filter, but isn't occlusion shaders supposed to work with volumetric lights?

Appreciate comments on this. It's not a big deal for me since there is ways around it, but it made me wonder if it's a bug or a feature :-)

/Slartibartfast

vector
02-19-2014, 09:58 PM
Well, I use to render separately the volumetric lighting pass for a best compositing (another scene where only that light is seen, I mean) because this way you can play with the opacity, color,etc later

Slartibartfast
02-20-2014, 08:26 AM
Ok, thanks for your reply vector! I'll try that approach. It sounds like a faster and more controllable way.

ary3d
02-20-2014, 09:58 AM
there is a problem with volumetric lights that affect some shaders, transparencies and occlusion.

I think that the volume of the light is like an object, so occlusion see it in that way and calculates in the render.

the workaround that Vector recommended is the way I use the most. but I duplicate the scene and apply matte to all object in the properties tab/render, black background, and turn off all unnecessary calculations like reflection, refraction, radiosity. other lights, so you can have shadows on your volumetric light

Slartibartfast
02-23-2014, 12:38 PM
Ok, thanks ary3d! Sounds clever. And I also thought about shaders seeing volume light as an object. I guess you can't switch "unseen by rays" to a light..