Roland wrote: ↑
Tue Apr 23, 2019 7:38 pm
I am attaching a doc that shows my efforts to use the TechDraw WB. And compare it with Drawing WB. Apparently I am not getting the TechDraw WB functional for my purpose. I am posting it here (rather than under "Use Questions") because it seems to me that TechDraw is still a bit buggy in view of my expectations. (Maybe it's an easy thing to solve, then we move this topic to another part of the forum)
You've discovered at least 2 bugs. Thank you for that.
The first bug is that OCC projection algorithm returns zero edges for ProjItem/Front, even though the input shape is valid.
The second bug is that OCC bounding box object fails on being queried for the extents of an empty bounding box.
If you change the Projection Direction of the Front view slightly (I used (1.0, 0.01, 0.0), then save and reload the document you'll get your Front view back.
You can also try the polygon approximation projection method (Coarse View property) or the perspective projection (Perspective property). They seem to handle the input shape and projection direction somewhat better.
git commit fbc542738c
addresses the empty bounding box failure.
"DVP::extractFaces - ProjItem002 -Can't make faces from projected edges"
This warning tells you that there are spurious edges in the projection of your shape. The face detection algorithm can not find unique paths around the Face regions. If you don't need Faces for hatching, you can uncheck the "Detect Faces" preference.
Although not perfect, with the Draw WB I can do a lot more (as you can see).
Drawing module's failure to display the Front view (Ortho_0_) is likely also due to the "no edges returned" error. The "Project shape" function also fails to produce a valid projection. TechDraw, Drawing views and Project shape all use very similar code to perform projections.
Again, thanks for your debugging help.