PYurCAD (pronounced PureCAD) requires only python3 (tested with 3.5.3 and 3.9.13) and the python standard libraries. It is a rewrite of Cadvas version 0.5.2 but without the use of the AppShell framework (and Python Mega Widgets). The impetus to do this came after I discovered a 3D graphics example in Bhaskar Chaudhary's recent book: "Tkinter GUI Application Development Blueprints, 2nd Edition". I had not realized that it was possible to do 3D graphics on the tkinter canvas. In his book, he also presents a "Paint" app which has a simple, clean and functional interface that I thought would work well for my CAD app. So here is the result of a couple of days of effort, the first step toward what will hopefully someday become a 3D CAD application written in Pure Python.
Actually, there is one additional library needed to enable loading and saving files in dxf format. To install it run pip install ezdxf.
Then download (or clone) this repository and run python pyurcad.py.
Further research on the topic of "3D graphics on tkinter canvas" turned up this work which shows several interesting 3D examples (for Python2). My next goal is to extend PyurCad to be able to extrude and display some basic 3D shapes.