Adding a surface to a Mesh that I've split?

Hi all -

I’m fairly new to rhino, and I seem to have gotten myself into a bit of messy situation with some meshes that I’ve been trying to prep for 3D printing (I’m making a city model with a circular base so had to trim to remove all that was sticking out of the circle).

I split the meshes to remove the parts that were sticking out of my circular layout (booleans were not working so I resorted to this solution), but now I’m stuck with open meshes and can’t get a surface to fit to them. I originally thought I could meshbooleanunion of meshbooleandifference my way out of it, but any booleans, splits or even doing it manually with intersections is falling. I’ve troubleshooted my booleans and tried to repair my model but still no results. I’ve also tried to fillmeshholes, but the geometry seems to complex and that also does not work…

I’m thinking there has to be a tool where I can pick the contour points of these open ends and draw a source onto them… sort of like the pencil in Sketchup? I’m posting a photo of the meshes with missing sides for better understanding of the situation

If anyone can help out, I’d really appreciate it.

Hi Emilie,

Mesh cutting and boolean operations are not super reliable in Rhino - just a warning for future work with meshes. There is a chance it will get improved in next version of Rhino. Looks like splitting worked for you though.

From here, I’d suggest looking into these commands:
_DupBorder - should extract the open edges of you mesh as polylines ( or use _DupEdge for specific edges ).
_MeshPolyline - will make a mesh patch from closed polyline. This way with a bit of cleanup you may be able to ‘cap’ yoy split meshes.
Use Join to join meshes into closed mesh objects for 3d printing.

You may also try running AlignMeshVertices to fix tiny tolerance problems that may cause the mesh not to be watertight



DupEdge + Meshpolyline worked beautifully!

Thank you so much Jarek!