I have a mesh imported from STEP. Its thickness is 0. How can I extrude it to make it thick?
Select that surface and project it.
Projection will create a new sketch, use loft to make it solid.
You can also use a negative Shell feature, I think
That’s the best way, thank you.
However, I have hundreds of polygons - is it possible to loft all of them at once? Do I have to select each pair individually?
Unfortunately Shell and negative Shell do not work.
You can in Onshape, the feature is called Thicken. You can import the STEP file and apply Thicken. Personal Hobby work is free but if that is an issue.
Freecad can do it, How to add thickness to a surface? - FreeCAD Forum
Side note, Shapr is not a surface modeler, it doesn’t know what to do with that kind of import when thickness is 0. 3d Model Imports should be 3 dimensional solid.