Vray falloff controlling reflections problem

[seandunderdale]

Hi,

Im using a Vray falloff to control the reflection amount of some shaders so I can re-create the effect of a polarising filter. Everything works fine when the falloff is plugged into the reflection amount of each shader. The problem arises when I try to batch render, or re-open a file and render. The settings are all wrong, as if it isnt pulling the info from the falloff node down to the shaders until I tweak it and make a change. Then it affects everything correctly again. So it seems like some kind of refresh issue.

All my batch renders look incorrect and too shiny. When I open the file and render it looks the same. If I RT the scene and change the value by a tiny amount, it pops back to how it should look (a lot less shiny).

Im using Vray 5 hotfix 2 with Maya 2020.

[seandunderdale]

Ive done some quick tests and I seem to be able to get it working in a simple test scene. Im hoping its something scene specific.

[seandunderdale]

Ive attached a scene. It seems when you attach a falloff to more than one shader, it only affects the first one you connect it to. The rest need to be "refreshed" in RT. But even then, they dont render correctly in production render.

Im currently making a falloff material for each shader, and using a master polarising falloff to control all the values. Tedious, but hoping it will will work.

[hermit.crab]

You seem to have sent the referenced falloff scene (although no falloff nodes are present). Could you send a one with the specific issue? Screencaps of the issue would be helpful as well. Otherwise, I made a few tests on a simple scene and don't see a difference between batch and Maya rendering. Do you mean that the Mix curve resets after a re-open?

[seandunderdale]

Sorry, I was in a mad rush when I found the problem and wasnt careful with my upload.

Here's a scene that should work. If you fire up RT and change the falloff explicit value to kill reflection from an angle, they all will work. If you then render in production vray, only one ball will get the reflection falloff.

Since one falloff can only be connected to one shader, Ive had to make a falloff for every shader I want to control, and a master falloff to control all the other falloffs....rather than one falloff controlling all shaders.

Also, the issue isnt between batch vs framebuffer vs maya etc. Its RT vs everything else. It seems fine in RT, but not in anything else.

[hermit.crab]

Thanks for the report. I've logged the issue (internal bug-tracker id: VMAYA-10316) for developer analysis. As a workaround try plugging the VRayFalloff's R channel (instead of its alpha) into the shaders' Reflection amount slots. You can do that through the Node editor.

[seandunderdale]

Thanks for looking into it, and also for the workaround. I think I normally would have tried an RGB channel option, but the falloff node didnt work unless I had ticked "Alpha from RGB intensity", so my assumption was it needed to be plugged into the alpha.