Vray RT not looking like render - vray car paint in blend material

[emartin8907]

Well, the RGB does, but one of my render elements, a material select, seems to change.

it is a vray car paint material that lives at the base of a blend material. the coat material is for reflection, which has its own material select. the vray car paint material itself has no coat, so i can separate reflections from the paint.

I lit the car in vray RT it looks great i render it and it looks wrong.





perhaps vray car paint material within a blend material doesn't work so well?
http://forums.chaosgroup.com/showthr...ight=car+paint

[svetlozar.draganov]

It would be better to provide the scene for investigation since I couldn't reproduce the issue on my sample scene here.
You can replace the car with a sphere or other basic primitive but don't change the materials, lights and other features important for the bug reproducing.
Let us also know what RT engine type you are are using.

[emartin8907]

Hi thanks for your reply,

Here is my scene with just a sphere.

PaintHelp.zip

Same thing happened when I made a sphere in the scene.

thanks for taking a look!

[svetlozar.draganov]

Ok I will need an explanation how to replicate the issue since everything here looks identical between Production and IPR.
Here is the RGB channel from Production and IPR:
Prod:
IPR:

CarPaint Materials select below:

Prod:
IPR:

CoatMtl is also almost identical.

What are the version of V-Ray/Maya and OS that you are using?

[emartin8907]

The problem only seems to happen when I refresh a Light in RT. either toggling it on/off or moving it causes RT to refresh and become way brighter.

I am SO confused.

I opened my scene from yesterday, launched RT, and it was dark just like my renders are coming out. Then I toggled my light on and off, and BOOM RT refreshed and got way brighter again. But when I render it is darker still.

This problem does NOT reproduce on just a sphere in my scene I just tested this, only is happening with my car model which is CAD and very heavy perhaps something is going on with the geometry that's causing this?

I swear I've used this shader set up before with these models and never had a problem...

Maybe for now I will go back to my shader set up I use for Nuke which is a more basic approach with 5 material selects for the different layers of paint which are just normal vray materials, I was trying to save some time with this project but now it seems that will be the faster route!

[emartin8907]

The problem seemed to have been something within my geometry, I exported out all geometry with paint assigned as an fbx, brought into new scene, problem gone. I'm re importing it into my scene now hopefully that will take care of it if not I'll just migrate to a new scene.

The problem occurred in the normal paint set up I used as well. the material selects looked like there were masked off by a world normals pass Could not recreate on simple primitives I made within the scene. Could not replicate on geometry once I exported it into a new scene. Tried conforming and reversing normals no help. So I don't know but am happy to see my render elements looking normal again!

[yolov]

In case you can share the scene in a state where it was producing issues for you, it could help us to get to the bottom of this.

[emartin8907]

sending you a pm now.
TEST_SCENE.ziphdr.zip

[tashko.zashev]

sending you a pm now.
[ATTACH]31740[/ATTACH][ATTACH]31741[/ATTACH]

Thanks for sharing your file.
Unfortunately I'm still missing something here because whatever changes I made to this scene (switching lights on/off, moving lights or objects) they were always being updated properly by the RT engine .
You mentioned that the issue can be reproduced only with specific geometry, but this file contains only a Sphere. Could you please attach this geometry or send it to support@chaosgroup.com?
I'm testing with the following software configuration:
Maya 2015 / V-Ray 3.40.03 / RT CPU