Prepass with BF?

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

Hey?

I’ve got an animation with BF and LC. After LC it does the merging of LC passes deal, but then it does a Prepass before it starts to render. Granted the prepass takes like 3 seconds, but still, WHY?

I have it setup that LC does not show the preview, so I’m expecting to SEE each frame change. But this mysterious prepass that only takes 3 seconds does show a preview that almost looks like a Reflection Channel and that messes up my VFB so I can’t see frame to frame the animation.

It does render and save each frame correctly however

?!?

2

Probably have ‘use interpolation’ ticked on one of your materials somewhere ?

3

But I’m rendering with a grey override and thats just a standard vray shader and all I changed was make the diffuse grey

4

A subsurface scattering material in the scene could also cause this.

5

I for sure do not have any of those in this scene. Not too much of a train smash as the renders are almost done, just nice to sometimes sit and watch the render

6

Not sure what’s in your scene, but recently I discovered at least some of Forest Pro grass presets use sss materials. I kept trying to find interpolation-active materials for hours, until I finally decided to check the FPP materials.

7

hmm yes I do have forest pack objects in the scene, will check them to see. But still, I’m using an override which should effectively mean that any other mats doesnt matter?

8

Nope, that wasnt it either. No sss in the scene

9

Check the V-Ray log file and look for something like “registered interpolation map for material…”

Best regards,
Vlado

10

I get this:
[2013/N/29|11:11:38] 1 interpolation maps registered
[2013/N/29|11:11:38] Rendering interpolation maps with minRate=-1 and maxRate=-1

but it doesnt say anything about which map or material

11

…and I’ve now made sure that no materials have this by running Olly’s VMC script and made sure that both reflection and refraction interpolation is OFF for all materials in the scene.

But still it does a prepass of 1 second

12

I use this for find all materials using interpolation. It also prints the names of guilty materials and the objects to which it is applied in the listener.

(
	clearListener()

	for m in getClassInstances vrayMtl processAllAmins:true do
	(
		if m.reflection_useInterpolation == true do
		(
			format "Material:% Applied to:%\n" m.name (refs.dependentNodes m)
			m.reflection_useInterpolation = false
		)
		if m.refraction_useInterpolation == true do
		(
			format "Material:% Applied to:%\n" m.name (refs.dependentNodes m)
			m.refraction_useInterpolation = false
		)
	)
)
13

I get:
-- Syntax error: at ), expected <factor>
-- In line: )

14

Sorry, I should have said you need to select ‘new script’ from the maxscript menu then paste the code into there. Then from the ‘Tools’ menu select ‘evaluate all’

15

I just get
“OK”
in the listener

and the maxscript window just changes the code into pretty colours

16

Ok, in that case there aren’t any materials using interpolation in your scene.

You can execute single lines of code in the listener but for multiple lines you need to use the maxscript window.

17

Would it be possible to send the scene for investigation ?

18

no sorry this is one of “those” projects which is hush hush for now

19

Dan, thanks this is soooo helpful!

20

You’re welcome. VMC will turn all interpolation off but sometimes it’s useful for know which materials/objects were using them to stop it happening again.