Visible mesh lines in caustics!?

[pentool]

Hello,

I've been playing with more glass/caustics stuff. I don't know if there's something with my settings (and if so, I'm not sure which one), but I'm getting this odd phenomena where the mesh lines are visible in the caustics. If I turn caustics off, there are no mesh lines visible.

Look at this first image. In the lower left shadow area where the caustics are present, you can see the fine mesh lines. I added a render-time smoothing of 3 iterations on the mesh.



Now look at the following image, where I've reduced the mesh smoothing from 3 to 2 iterations. Clearly, the mesh lines are changed now - as you can see again in the shadow area. It's fairly simple and straightforward stuff. Is there something wrong with my settings somewhere?



Thanks!
PS: I just used the default VRay caustics settings.

[Candelero]

What is the glass material setup ?

Best regards,
nikki Candelero

[pentool]

It seems that this is an issue only with curved surfaces. The following image has 2 box objects with 4 length segments and the same glass material. The rear object is assigned a bend modifier, the front isn't. Since the rear object is curved, the 4 mesh segments are visible.

[vlado]

Unfortunately, this is a thing that cannot be corrected. The actual geometry does consist of flat triangles, and interpolated normals cannot completely hide this fact.

Similar to how an object's outline depends on its actual geometry, the caustics pattern depends on that geometry too, and this is apparent in the result.

This is not a V-Ray specific issue, you are likely to come across this in any other renderer.

Best regards,
Vlado

[pentool]

I see. Well, thanks for the info, vlado! I've found that if I crank up the segment count - in this last glass example to 48 - then the lines virtually disappear (on the curved one).