I modeled a small part (from inside a cheap Web cam I had disassembled) using direct modeling and editing in the new Bricscad V12.
Modeling it was straight forward. For instance, I drew a square from a polyline, and then used the new Quad cursor to extrude it into a box. Or, extruded two circles, and then subtracted one from the other to create the a cylinder with a hole. If you have used 3D ACIS modeling in AutoCAD, then none of this is new.
I union-ed all the bits that make up the part. In the figure above, you see the real-time shaded mode in which you work, along with the gradiated background. (Hidden lines are shown only when editing parts.) To the left is the quad-cursor, and the blue color highlighting the currently selected feature.
One mild irritation is that I found I needed to switch between Quad cursor and the regular cursor for certain operations.
What I wanted to see was this: how easy was it to modify the model? Specifically, I made two holes too big by mixing diameter for radius.
While fiddling with the model, I noticed an interesting effect during direct editing. As long as the editing action is OK, the entire model takes on a green hue; when my cursor dragged a part too far, the entire model changed to orange as a warning.
Finally I found the solution to resizing a hole: grab its inner wall with the Quad cursor, and then use the default push-pull function to resize. In this case, I entered 0.5 (into the dynamic dimension) and pressed Enter.
One other irritation is that this new 3D stuff is not yet fully documented, so there are things happening that puzzle me. For instance, sometimes a casual looking X appears on the model, but I don't know what it means.