What causes this artifacting?

[Bosseye]

Hi all,

Does anyone know what causes this curious black smudge artifact on the back corner of my sink messing up the white ceramic material? See the pics. I've used the sketchup plugin that lets you round off/bevel edges easily which usually works brilliantly, and theres nothing obviously wrong with the model - so not sure whats causing this error to appear on the render. Maybe a subdivision/smoothing thing?

And apologies, not the greatest images I know, but hopefully you can see the issue.

Cheers

Error2.JPG (12.54 KiB) Viewed 5232 times

[Polinalkrimizei]

That one does look like a normal-related issue, for example if there are long and thin triangles in your mesh. Can sketchup do wireframe images? Sorry I'm just not familiar with that program.

If you subdivide the mesh in indigo, the area should get smaller. That is not meant as a solution (unless you subdivide infinite times...), just to check.
If it indeed is a normal issue and you post the mesh, I could try to fix it with blender.

[Bosseye]

Thanks for the offer

I'm fairly sure its not a normals issue as all faces are pointing the correct way - it seems to be a smoothing problem with the mesh. I've been fiddling around with the soften/smooth command along with the bevel edge command and turning on 'soften co-planar' seems to help so for now I have a workaround.

[Pikadili89]

Its just a reflaction of black marble if you ask me, it looks like end of the black marble on the wall side is reflecting on your ceramic basin. And reflection of basin on black marble

[CTZn]

Polinalkrimizei is right in this regard: faces smoothness is defined by how their respectives normals relate with their neighbours.

On a smooth and curved surface, face normals may be not orthogonal to their triangle, but ideally merged with the neighbouring triangles normals.

[Polinalkrimizei]

Yeah, this does actually happen quite regularly when importing objects from CAD programs that don't care much about mesh topology...
In Blender it usually can be fixed by making quads out of the triangles or by cutting them in half... but why does Indigo have this problem?!

[StompinTom]

Yeah, this does actually happen quite regularly when importing objects from CAD programs that don't care much about mesh topology...
In Blender it usually can be fixed by making quads out of the triangles or by cutting them in half... but why does Indigo have this problem?!

Definitely a normal smoothing problem. In Blender it can be fixed most of the time with an Edge split modifier or manually separating the faces.

[CTZn]

Yeah, meaning that "Indigo does not have this problem" I think, rather "the mesh came with it packed".

SketchUp might well have it's own ways of displaying geometry though (it has a greater tolerance, I'd say naively), wich may turn into a problem when it comes to data exchange.

[CTZn]

Oh wait. I think you just need to set explicitly the curved angle to be hard, it's smooth I bet and that is wrong.

If that doesn't work then there is some precision issue perhaps, try splitting larges surfaces into smaller chunks as suggested (add construction lines).