List of the various different pre-passes?

V-Ray V-Ray for 3ds Max General
1

Hi folks,

Is there a clear list of what could cause vray to run a “pre-pass”?

My understanding is that they occur whenever you use GI and/or whenever you use interpolation (reflection or refraction). But are there additional things that result in vray needing to run a pre-pass before the main “Rendering image…” pass?

I have a scene right now that uses no interpolation on any materials, no displacement, but seems to run through a particular pre-pass that is darker than the initial GI pass and looks suspiciously like an interpolation pre-pass but isn’t. I’m wondering if I have a rogue material or object that’s causing this and might be slowing the render down.

Can’t post the scene due to NDA unfortunately.

Cheers,

2

Sounds almost certainly like it’s either an SSS prepass or a reflection/refraction interpolation prepass. Check your materials.

3

Yep that was my first thought but I ran the VMC script on the scene and removed any trace of interpolation. There might be some SSS left over from a dodgy imported model though, I hadn’t thought of that, will re-run the script!

Cheers,

4

Do you have any SSS or skin material set to pre-pass mode? Also do you still get the pre-pass if you override the scene materials?

5

I’m currently rushing to get this out the door but once it’s done I will start diagnosing the scene and will report back.

Thanks,

6

VMC is awesome, but Zorb is your best friend to have a bird eye on your scene.
You’ll definitely pick us straight if there is some SSS and be able to select to object containing it to resolve the issue.

My 2 cents :wink:

Stan