[bjorn.syse]

Hi,

I noticed this effect when rendering a solid cube with chamfered edges. Have a look near the edges of the leftmost cube. The white streaks coming from the chamfer behind it looks weird. Is this the way it is supposted to look?

Cubes are 10 mm side, with a .02 mm chamfer. Using the preset "Plastic (Red)" SSS material.



Regards,

- Björn

[-Adrian]

Not correct i think, probably a render limitation. Is the chamfer mesh cleanly closed/welded?

[bjorn.syse]

I guess it is, since this is nurbs, and that ought to be handled by rhinos mesher or perhaps the plugin upon export... I see the same effect if using fillets instead, just a bit smaller (probably beacause a fillet will eventually turn out as a chamfer in the end depending on how many polys it generates.. )

[Cadhorn]

bjorn: if you select one of the cubes that's not rendering correctly and look at the object properties (command: what) does it list the object as a closed polysurface? sometimes filleting or chamfering edges screws things up a bit.

this happens to me all the time. if the tolerance isn't set small enough, rhino might chamfer things "sloppy".

if it is a valid closed object... then idunno

[bjorn.syse]

Cadhord, thanks for the tip. But it seems it is a closed polysurface and has no naked edges...

- björn

[Maximus3D]

Try increasing the meshing quality in Rhino so Maxwell has a denser mesh to work with, maybe that solves the problem.

/ Max

[bjorn.syse]

Maximus, thanks for the tip, but a cube that is chamfered doesn't really change it's geometry if it gets more polys, does it? Since there are no curved surfaces I mean,..

[nachob]

Is that cube an instance?, there is a known bug with instances and SSS

nachob

[bjorn.syse]

Not really, It is a Rhino block, but I never exported it as an instance... however that was my plan.

Any other thoughts?

[polynurb]

it could well be a welding issue.. just like with displacement mappings on 90° corners.
when you _extractRendermesh from the nurbs cube, you should find the edge vertex points not welded. that's correct as Rhino should display the cube with sharp edges, and since the vertex points share the same coordinates, the mesh is closed, and exportable as closed .stl volume.
however that may lead to problems ... 3d studio's STL check still finds error in such an unwelded mesh, and using displacement maps rips the corners open.
I would try :
A- weld the rendermesh with 91° or more (it will destroy your UV texture coordinates)
B- chamfer or fillet the edges (better for preserving Packed coordinates)
C- Try a T-spline cube (I know you have it )