topic Need Help with Plane Cut and Separate Shells in Meshmixer Forum

Need Help with Plane Cut and Separate Shells

rene.wenus — Thu, 06 Feb 2020 07:19:19 GMT

Hello i have a Problem and im searching 3 Days for an solution but i dont find anything that works.

I have different STL files but always the same problem.

I import the STL in Meshmixer and first i make a Analyse/Repair to the Model. I need more Plane Cuts and Pins for printing. So Next step i select a section and make a Plane Cut. After this i go to edit/separate shells. Now i want 2 shells in the object browser but i become 90 shells. If i sort them and combine, after the next cut again i become x many shells. I hope you can imagine my problem and help me.

PS excuse my english.

greetings Rene

Re: Need Help with Plane Cut and Separate Shells

Anonymous — Thu, 06 Feb 2020 11:31:32 GMT

Check if your source mesh if composed by several not connected shells doing some test SeparateObjects.

If this already results in several objects consider to join them to a single watertight object (ie. running EDIT/MakeSolid or joining the objects via BooleanUnion).
If MM finds only one shell (or two in case of a hollow object) your cutting plane cuts it several times (e.g. if you do a vertical cut in a "S" shape). In this case (e.g. if you want to cut on the upper intersection of the S only) you need to run a selection based PlaneCut: Run Select and select the region where the cut is restricted to. Run Edit/PlaneCut inside SELECT.

On noisy it may happen the a global cut cuts tiny "peaks" of a tangent surface. This case run ANALYSIS/Inspector before SeparateShells and dim down the SmallThresh slider to detect only these small peaks.

If you do not want or an not combine loose pieces: Instead of doing a global separate action (EDIT/SeparateShells), there's also a selection based Separate: Navigate to a view along the cut done before and run SELECT. Click on empty space near the former cut > a red line will be drawn. generate a polygon roughly including one half but not touching the other. Now hit E to expand the selection to get one half selected totally. Now run EDIT/Separate inside SELECT.

Re: Need Help with Plane Cut and Separate Shells

rene.wenus — Sat, 08 Feb 2020 14:21:25 GMT

Thank you so much that helps me a lot. Make Solid was the right way for me.