trace sets, self reflection, Next GPU

[super gnu]

ive got an object, and a client who doenst like the self-reflections.

scene is rendering in Next GPU.

Tried adding the object to its own trace set/ reflection exclude list, but it makes no difference.

Not sure if this is a trace-set limitation or a GPU limitation.


for now ive resolved it by turning off "visible in reflections" but i think this will cause me big problems later.

[super gnu]

nobody? i really need this object to not cast self-reflections, whilst at the same time being visible in other objects (its a can with water drops on... if i turn off "visible in reflections" for can entirely, the can looks how they want, but the droplets get bright around edges, since they are reflecting environment and not can.)


on cpu i can duplicate can, inset it slightly, allow that to reflect in droplets, but exclude it from main can using trace sets.. however A) this is very hacky and B) even that doesnt work on gpu.

so far the only potential solution is to render the water drops as a seperate pass. which, given its an animation, add a significant cost to the job.

[savage309]

Maybe a kind of long shot - but can you use the VRayMtl Dim Distance for that too?

Best,
Blago.

[^Lele^]

ive got an object, and a client who doenst like the self-reflections.

scene is rendering in Next GPU.

Tried adding the object to its own trace set/ reflection exclude list, but it makes no difference.

Not sure if this is a trace-set limitation or a GPU limitation.


for now ive resolved it by turning off "visible in reflections" but i think this will cause me big problems later.

but 2 render passes, and the object's mask should be enough. What wouldn't work, in that case (keeping in mind the setup isn't quite physical)?

f.e., below: plain render, object mask on top with the "sphere" non reflecting, and the (in-vfb) final comp.
I see the issue as being the object self-reflecting in the reflections (ie. secondary rays and up), but i think it could only be cured with LPEs, and even then, it'd likely be quite the pain.

[super gnu]

thanks for the helpful replies guys.. the main issue with doing 2 renders is just the extra rendertime. its a tight deadline for a difficult client. we are already over schedule and budget. it also gets complicated (maybe) with the fact i have to deal with the refraction of the can in the drops. if i render a pass for the drops, then add them over the non-reflective can with a mask, the can seen through the drops will have self-reflection. im sure there are ways to fix this in comp, but i cant be adding tons of extra complexity at this stage.. im not a comping expert really.

dim distance might just work.. does it work on gpu? if i set it to some small value i might be able to find a sweet spot where it reflects in the droplets, but kills the reflection they dont like on the object.


quick nooby question, whats LPE's?

another question.. is it possible (on cpu at least) to add an object to its own exclude trace set? if not, could it be? and, assuming that trace sets dont work on gpu, are they anywhere near the top of the "great list"?

[^Lele^]

LPEs = Light Path Expressions.
F.e.: https://rmanwiki.pixar.com/display/R...th+Expressions

[savage309]

dim distance might just work.. does it work on gpu?

Should work in GPU with V-Ray Next, Update 1. Was added because of a similar request in a use case close to the one you have.

Best,
Blago.