Tips and Tricks
[NOTE: These tips are for meshmixer02. ]Meshes
meshmixer works best with reasonably dense meshes. Trying to paste a part in a region that has only a few triangles or quads may fail, or produce undesirable results.
Cutting/Erasing
meshmixer works best when removing parts that are geodesically convex, meaning that they are roughly circular or elliptical on the surface. If your selection region is highly non-convex, such as a C-shaped region, you may see foldovers in the fill surface.
If you are dropping a part onto a rougher surface, or over a region where the surface normal varies a lot, try pressing the 'n' key to smooth the normals of the underlying mesh. This relaxes the mapping of the part to the surface.
Pasting
If, when you try to drop a part, meshmixer tells you that it "Cannot Stitch", look closely at the green region surrounding your part. The stitching is probably failing because the edge of the part is sticking out past the green region. You can fix this by increasing the ROI Scale until the green region completely surrounds the part.
If you want the part you are pasting to have a sharp transition at the boundary, un-check the Optimize box in the DragDrop Options.
If you would like to move a part with a sharp boundary from one smooth surface to another, try including part of the surrounding smooth surface.
If you are having trouble getting a boundary that is as smooth as you would like, try dropping your part on an intermediate surface, like the sphere.obj file included in the \models\ folder. It may help to increase the Smooth setting in the DragDrop Options. Then select the part again and move it to the final surface.
meshmixer has trouble dropping parts on surface with lots of detail. You will get better results if you prep the surface first, by erasing any complicated features you want to paste on top of. For example, if you wanted to paste a different ear onto a head, you should remove the existing ear first.
Parts
Parts are stored in the folder C:\Program Files\MeshMixer\parts_default. If you would like to save parts for later, or make multiple part libraries, just copy the contents of this folder to another.
Part files are just .OBJ meshes with a few specific properties. In particular, they are open meshes where the exterior boundary loop has UV coordinates such that the length of the loop is the same in UV-space and in 3D. So you can use any open mesh with appropriately-scaled UV's. The normals of the boundary loop are also important - they are actually the normals of the underlying surface the part was cut from. But you can correct for this using the Bulge setting in the DragDrop Options (it will also help to un-check the Optimizebox)