glass bulbs rendering black...

V-Ray for Maya V-Ray for Maya :: General
1

Hi,

Rendering cars, some glass parts in the headlights/ tail lights are rendering black even though they show up normal in RT.

Example;

RT;

Rendered;

Tried upping Depth to 24 on refraction as well as reflection attributes on the material.
Affect shadows are on in refraction.
Tried playing with bias and fog multiplier.

I am using vray universal method;
adaptive, min shading rate 2, min subd 1 max subd 100 threshold .005 subd mult 1

AmberRT.jpg
AmberRT.jpg1000×909 55.2 KB

AmberRendered.jpg
AmberRendered.jpg1000×920 85.7 KB

2

Object is visible to refraction and has proper normals I assume?

3

Yes refraction is on normals are fine. I will post the material tomorrow in a test scene

4

Looking forward for that scene :slight_smile:

5

Here is a test scene with a sphere.

It is rendering black, I have been cheating this by lowering the opacity of the shader but I would prefer real refraction!
BulbTesting.zip (155 KB)

6

You have environment override on with refraction set to black. So its returning black from environment since its set to black in override environment tab. Dome generally does not affect refraction I don’t think, so if you were to use hdr you would have to plug it into the environment override refraction.

For the object behind the glass, first you need to give the sphere thickness then it should return proper color. I’ve put a grey sphere ito the glass and gave the glass sphere thickness. Otherwise it treats the whole sphere as a solid refractive object.
BulbTesting1_scn.zip (4.2 KB)

7

The dome light was is to invisible, so there isn’t what to refract

8

Hmm that test scene wasn’t the best, thank you all for your answers though.

The glass in my car model is double sided geometry.

Here is a pic of my problem

with glass material opacity lowered, it looks how i want it to;

but when i raise the opacity all the way, it gets dark

Opacity100.jpg
Opacity100.jpg640×483 98.5 KB

LowOpacity.jpg
LowOpacity.jpg640×483 63.8 KB

9

can you post just this part of your scene…

10

Unfortunately I can’t share any of this geometry its CAD from manufacturer.

Do I need to plug the hdr into env overrides or can I just turn env overrides off?

Experimenting with plugging hdr into env overrides now.

was hoping it was something in render settings hmm

EDIT just tried env overrides and made no difference with hdr plugged into everything or having them turned off.

11

well it will be hard to say what’s really happening in your scene without actual geo. As you saw in the example it works correctly…

12

So the vray universal settings should be good?

Do I need to increase the subdivisions for the glass material? Is there an override to have only certain materials with higher subdivisions than the rest of the scene?

Perhaps I can send you a simplified scene with just a headlight?

13

yeah its what I said, just the headlight which demonstrates the issue. I don’t think universal settings will make a difference.

14

Thank you so much for taking a look Dmitry!!

He showed me I needed to increase the max depth values for refraction/reflection in not only the glass material but the chrome that was underneath it. I never realized this!

15

Hi,

I would like to ask if ChaosGroup is thinking of adding a feature into the Vray material , where you can put even to a single surface a virtual thickness (as it is e.g. in MR materials). It would be very useful and nice.

Martin