Bump map causes edge artifacts

[kosso_olli]

Hey,
I know this problem here has been mentioned a dozen of times, but I want to raise the awareness for this again. Can this annoying problem, that has been known to show up in V-Ray occasionally for quite a few years now, finally be fixed? Honestly, V-Ray must be the only render engine where I have ever seen this.
Yes, I know this can be fixed by raising the tesselation of the oject. But that is no option for us, as this is pre-tesselated NURBS data.









Best regards

Oliver

EDIT: Added more pictures to better illustrate the prolem.

[kosso_olli]

No one? Thats sad...

[Morbid Angel]

it could be due to the fact that the final geometry normals are locked so modifying them with bump map produces this result. What happens if you unlock the normals? Additionally can you post this piece of geo with bump map included here for inspection?

[kosso_olli]

Dmitry, what do you mean by unlocking the normals? It is geometry from Nurbs, so likely modifying the normals will instantly break them.

[Morbid Angel]

Well, I don't believe vray renders nurbs directly, rather it tessellates it into poly under the hood. During that process the normal data is derived and locked from nurbs data, at least this is how it works in maya. Modifying it on top of that could cause some issues.

[kosso_olli]

Yes, we get the tesselated data from Catia files. We do not modify the normals at all.

[Svetlozar Draganov]

Like Morbid Angel suggested, can we have a sample of the scene for investigation?

[kosso_olli]

Svetlozar,
the scene file was sent, the ticket number is 153-911-019

Thank you!

[kosso_olli]

Was the issue ever fixed? I still get this from time to time.

[PIXELBOX_SRO]

We get this very often with bump maps.
No idea if its being addressed.
Last time i remember Vlado said hes on it, but where this bug is now, no one knows.
Its an elementary thing you would expect from a render engine to tackle with a breeze.
And yes, only Vray has these artifacts. Its a shame it being put somewhere among minor bugs. For me this is a big thing personally.

[kosso_olli]

For me as well!

[salvadoresz]

I dont know how Catia nurbs get imported into max, but i worked alot with Alias and Inventor nurbs. This was a couple/few of years ago so i dont remember exactly, but there are a few ways to crank up the tessalation.
1. When you import the nurbs into 3ds max, it gets imported as an Object, which has some viewport and render tessalation settings. 99% of the time i had to crank up the edge lenght, and sometimes i even put an edit poly modifier on top just to get rid of artifacts.
2. Translator plugins, loooong ago i used Npower's translators, they worked very well, allowing you to do all sorts of things after you import nurbs, like you could do further boolean stuff, and mapping options etc., besides tessalation options. https://www.npowersoftware.com/

Hope this helps

[kosso_olli]

Yes, I know this can be fixed by raising the tesselation of the oject. But that is no option for us, as this is pre-tesselated NURBS data.

That is not an option for me because of the reason mentioned right in the first post. Thank you.

[PIXELBOX_SRO]

this should work without any workarounds, its a really "primitive" bug - but i dare say the same about the fix

[salvadoresz]

So it's mesh data you're working with and not actual nurbs. Until this is fixed, did you try inspecting smoothing groups? Because this also looks like the smoothing groups are out of whack. try assigning the same smoothing group to the whole side of the tire that should be smooth, then you can also try adding a turbo smooth with smoothing groups checked?
Sorry if i'm just irritating you more. Btw, very awesome stuff in your portfolio