Help with complex mesh

I would love to get some help with this problem. I am self taught so I am sure there are things I could be doing more easily or efficiently, but I am flowing a complex mesh onto a solid and then trying to cut away the extraneous parts by splitting the solid and just deleting the extra pieces. The problem I am running into is that When the mesh is flowed onto the solid, I have a hard time splitting the solid unless I scale it down so that the mesh runs through all of the faces. Then when I scale it back up the parts do not line up exactly. I don’t know how to either split the solid so that all of the parts can be joined easily, or easily fill all of the mesh holes created when I scale the solid back up.
thanks in advance for your help! Round ring modified 2:28:16 parts.3dm (16.6 MB)

Problem is that your mesh exported from blender do not lines with the solid - if you look at it in side view you can se that the top edge is not planar (bottom edge too) - the mesh is skewed and do not intersects correctly with solid, which is perfectly geometric.

@cwreckord, is this what you want ? Round ring modified 2_28_16 parts_cg.3dm (5.6 MB)

Short description: I´ve used _ShowEdges and saw many naked edges, which i mostly fixed using _Weld 180. Then i´ve fixed the seam area, so the displacement roughly matches. Welded again so i was finally able to use _SelNakedMeshEdgePt which lets me select the upper and lower rows of mesh points. I´ve unselected either one and then used _SetPt to constrain boths edge rows to one z-height.

At the end i´ve been able to use _DupBorder to get the rows as polylines, _PlanarSrf to cap them and then i´ve removed the inner cylinder. I guess this is a bit more work required than needed. If this mesh was made from a displacement texture, which is what it looks like, you might do it all in Rhino. But before, you may make sure the texture is seamless in one direction so your mesh will line up at the seam of the ring.


Wow. I don’t want to tell you how long it took me to try to figure this out. Thank you so much @clement ! And I really appreciate you explaining what you did. I have done all of the Lynda tutorials, and look up things, am planning to do the level 1 course in a couple of weeks but if you have any other suggestions about how to learn let me know! Trying to learn as much as possible!

@clement I wonder if you can answer a question for me. I am working to finish this and there are some naked edges along one of the seams of the inside of the ring. Why is that the case and not on the other? And how would I go about fixing it? It seems as if there are two points on top of one another but if I delete one it deletes a face and they don’t seem to want to weld. Thanks!

@cwreckord, it can be fixed without much work:

  • Explode the model
  • You now have 4 meshes, select the inside ring
  • Weld with 180 degree
  • join everything up
  • Check for naked edges using _ShowEdes

There are only the naked edges remaining which are required to display the sharp edges. If this would be printed, you can get get rid of all naked edges using _Weld 180 performed on the whole part.


Thanks @clement! I have one more question which I am exploring. I would like to fillet the edges of the ring, so I tried going from mesh to NURBS in order to fillet, but as you can imagine the polysurface is complex. Every time I try to simplify it with MergeAllFaces it crashes. Is that because of my computer or can it not be done? I don’t know of another way to fillet, because filleting the mesh isn’t possible as far as I have found. I guess the best way is probably to start again and fillet before making a mesh but I am trying to avoid that if possible. Thank you!

@cwreckord, your object is a mesh object. Rhino is more oriented about Nurbs surface modeling, so there is no command to fillet mesh edges. To get a fillet, at least between the inner ring and cap surfaces, you´ll have to rebuilt the object using nurbs surfaces which is not an easy task as you´ve discovered. The displacement of the outer ring is too detailed to built a nurbs surface from it without degradation. The two caps and inner cylinder where easy to rebuild.

Below is a file, the displacement is still a mesh, the inner ring and caps are nurbs surfaces, all 3 joined together. To make the fillet use _FilletEdge. Once done, convert the Polysurface into a mesh using the _Mesh command. The result can then be joined to your displaced mesh. So you´ll have the inner fillets. Creating fillets between the cap surfaces and the displaced mesh is better done in a mesh modeler i guess.

Round ring modified 2_28_16 parts_cg_2.3dm (6.4 MB)

btw, you might take a look at the _ApplyDisplacement command in Rhino. The command is used to displace a nurbs surface using textures or procedural patterns. It might be easier to create your ring using a nurbs tube with all the required roundings, then create a black&white texture to mask a displacement applied to the whole object.


@clement. Thank you again! I really appreciate your help. I have tried mesh mixer, which I have a harder time learning as I can’t find as many tutorials for it, but I am signed up to take the level 1 Rhino course soon so hopefully I won’t have as many questions! Thanks again!