I've been using FreeCAD for about 18 months now, both 0.16 and 0.17. Just recently, it started displaying 3D non-transparent sketches as a strange combination of wireframe + transparent + shaded. For example, a simple cube shows up as this:
Note that all faces and lines are visible, even though transparency is turned off. This is "Flat lines" mode. I'm expecting it to look like this:
I've tried everything, including all the options under View > Draw Style, changing settings under Appearance, trying different levels of transparency, trying different materials - nothing gets me back to something that looks like the second image above, where hidden faces and lines are hidden. I tried uninstalling and reinstalling FreeCAD 0.16. I tried uninstalling and reinstalling FreeCAD 0.17 and it, too, has the same problem. I've tried rebooting the PC. I haven't changed graphics cards or made any other changes to my system.
When I use the "Shaded" draw style, I get a cube that is strangely shaded. It looks like either faces are missing or faces are transparent, depending on the lighting angle:
This was working fine for almost 18 months with just the standard program defaults, and now it has mysteriously changed. In "Flat lines" mode, the model rapidly becomes very difficult to interpret as it gets more complex with lines and faces all blending together.
Any suggestions?