VRay glass problem

[HAL-E]

Hello, does anybody have an idea where those strange patterns on my glass come from?

I just can't figure it out...

Material settings:

refl. / refr. glossiness = 1, fresnel ior 1.6, max depth 10, options: reflect on backside

Render settings (rendered with hdri (vray dome light)):

no reflective gi caustics, 1.bounces irr map. 2.bounces brute force, dmc sampler: adaptive amount: 0.85, noise threshold: 0.002, min samples: 8

I also enhanced my "Secondary rays bias" on the global switches rollout, but the result wasn't any better.

Thanks for any help!

[hzs_id]

It is possibly from the hdri, try rotating the hdri or changing it

Cheers

[TheMulf]

I would intersect it with a poly/mesh plane, to test if its a refraction issue.

[vance3d]

i'd try a couple things like rendering without gi and the hdri to see if its the geometry. almost looks like a smoothing group thing.

V Miller

[tricky]

I was going to suggest a smoothing group issue. Was the object modelled in Max or imported?

[HAL-E]

Thank you very much for your suggestions! it was in deed a smoothing group issue. The object was modelled in Max and now I tried some different smoothing group angles. In my opinion smoothing group angle 10 looks best.

Cheers!

[Morbid Angel]

i think the fundemental issue is a bad topology on your model. Which results in inproper normals and the result you get.

[stevesideas]

If you were to apply the same shader to a cylinder there wouldnt be any problems. Can you not build a low poly version of that tube in max and then turbosmooth. You should be able to get very accurate results based on that cad model..you woulnt have any errors then.

Sorry, just read above you modelled in max. I think you need to concentrate on doing a low poly version that can be smoothed...its much easier doing it that way. A single cylinder with the holes and then apply a shell.