I used the Cookie SOP to make a hole in a box. When applying a shader to it, Mantra renders the object with very ugly edges crossing the faces. I tried to use the Facet SOP to make unique points, but this doesn't work either. What can I do?

Hey Draetsch,

Append a Facet SOP after the Cookie then turn on “Cusp Polygons” & set an angle of, say, 89 degrees.

I hope the above helps!

Cheers!
steven

Sorry, doesn't work for me. Even with that I have strange highlights on the surface.
I had a simple setup: A polycube and a polytube subtracted ending with a cube with a hole. Now the strange edges go from the cornerpoints of the cube to the hole. The specular highlights are broken at this edges.

Hi there,

Can you please try the following?

a. Box SOP (defaults)

b. Tube SOP ( Polygon, Z-Axis, radius 0.4, 0.4 & height 2 )

c. Append a Cookie SOP to the Box SOP & connect the Tube SOP to the second input.

d. Change the Operation of the Cookie SOP to A minus B.

e. Append a Facet SOP after the Cookie, turn on Cusp Polygons & set the Cusp Angle to 89.

Do you still see the strange highlights with the above setup?

Cheers!
steven

I tried it out and it works partly. The problem seems to be the Anisotropic shading mode. I applied a shader SOP and created a VEX shader with an Anisotropic Lighting model. That doesn't seem to work. No problem with Phong or other models though.

Hi Draetsch,

Anisotropic shading does not work too well with non-subdivided polygons as explained in the Lighting Model VOP help.
/vex/surface1 -> ophelp lighting
.
.
Avoid using the Anisotropic Specular model on non-subdivided polygonal geometry because it will look flat shaded.
.
.

Is it possible to use Nurbs for what you want to do?

Cheers!
steven