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Help Part workspace features

Mesh to solid

Turn an imported STL, OBJ or 3MF mesh into an exact solid, so fillets, holes and STEP export work on it.

  • Mesh to solid AdvancedPart workspace toolbar
What other CAD programs call it
SchoolCADOnshapeFusionSOLIDWORKS
Mesh to solidMesh to solid (not in Onshape)Convert Mesh (Prismatic)Convert to Body

A mesh (an imported STL, OBJ or 3MF file, such as a model from Thingiverse or Printables) is only triangles. You can measure it, sketch on its flat faces and 3D print it, but a fillet, a chamfer or a hole that follows its shape needs a real solid. Mesh to solid rebuilds it as one (Fusion: Convert Mesh, Prismatic · SOLIDWORKS: Convert to Body):

  • each flat face becomes one exact flat face, however many triangles it was made of;
  • each plain round face (a hole, a peg, a rounded corner, the side of a cylinder) becomes one exact cylinder, the size it was drawn, not the size of its facets;
  • other curved faces (a ball, a scan, a sculpted figure) keep their facets, as small flat faces.

How to use it#

  1. Import the STL, OBJ or 3MF file.
  2. Click Mesh to solid (in Advanced, with Import), or press ` and type mesh.
  3. Tick the mesh parts to convert. The dialog says what each became: 12 flat faces, 3 cylinders.
  4. Click OK. From here on, the part works like one you made: Fillet, chamfer, Hole, Shell, and Export STEP with true round holes.

It needs the 3D engine (Exact geometry: on in the bottom bar).

Tips#

  • Models made in a CAD program (brackets, enclosures, parts with holes) convert best: almost every face becomes exact. A figure or a scan stays faceted, which is still a solid you can cut, but has no round faces to fillet.
  • A hole that comes out of a sloping face, or a round face that is not a plain cylinder (a cone, a dome), keeps its facets.
  • Fillets and chamfers that were in the original model are kept: a rounded edge becomes a cylinder.

If it does not work#

  • … is not a closed, watertight mesh. The mesh has gaps, or faces inside out. Repair it where it came from (in Bambu Studio or PrusaSlicer: right-click → Fix model), export it again and import that.
  • … is mostly free-form curves, with too many facets. A scan or a sculpture has too many triangles to make into faces. Keep it as a mesh: it can still be 3D printed, measured and sketched on.
  • … is already a solid. That part was a solid already (a STEP import, or a part you made), so nothing changed.