FreeCAD needed a good drawing program and TechDraw is a good one. Remember back when we were all struggling with the Drawing Workbench, for you to take on a project like TechDraw and to make make it work is one huge accomplishment. I'm sure your work will be used by thousands of users for years to c...
Here is another option. Create a datum plane above the shape and scar the surface with a sketch. This gives you two lines ( in Green) to create an additional datum plane that is tangent, we are splitting hairs here but at least this gives alot of control on all surfaces.
In this case, using Sketchers copy tool is the best coarse, you would need to recreate the constraint to the top external geo. for each copy. This way all the sketch copies are in one sketch.
You can also use a basic copy/paste. Copy a sketch without dependencies and paste it, then drag it into the body. Open the new sketch and drag the constrained sketch to the new location.
Good work flow, PartDesign is a great place to start. It does automatic things for you like opening sketches and it has good tree structure. If I were to model a structure I would put a datum plane (one on each wall) and then put all my sketches on the planes. You can attach multiple sketches to one...
How do you test before committing? I run it on my machine and copy the changes to github, I also copy the code out and run it local if I need to. I wonder about the wisdom of that approach. There is no wisdom in my approach. For me to work on this and use git I will need to set up yet another compu...
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