I found that, sometimes, to "create a link to an external geometry", you have to roll your Sketch over and work on the Backside. Then, you can't Select any Endpoints unless you roll the Sketch back over and work on the Frontside.
Also explored Symmetry Constraints, as Sketcher Lecture favors Geometric Constraints over Dimensional, and found out also why it cautions against over-depending on Symmetry. Lots of Partial Redundancies to clear out, yes.
I had a Model with every Sketch but one Attached Offset from a Base Plane. The one Sketch Attached to a Generated Face was a few circles, Constrained between a couple External Geometry Vertexes, for Pad and Fillet, then Transform to a Linear Pattern.
The Model needed one last tweak, to move two vertical Lines farther apart, on the very first Sketch, nowhere near the External Geometry Vertexes and not Constrained to them in any way, and the Pad off that Sketch adjusted perfectly. The Linear Pattern, though, collapsed. The two External Geometry Vertexes somehow turned to Skew Lines on all three Base Planes, and the Circle Elements scattered hither and yon.
Deleted all the External Geometry Elements off the List, but when trying to re-establish an External Geometry Vertex, FreeCAD only displayed these Skew Lines instead.
Tried Restraining the Circle Elements to a Construction Line instead, but by then I had Alarms all over the whole Tree, and the more things I fixed, the more mixed up the Features got so I couldn't hardly tell which Fillets were on which Features, and I just gave up, hafta go back and start from scratch. I need to be able to take the Tree apart and re-arrange it.
Searched for a way to Un-Depend its Features and Re-Depend them elsewhere, but the only thing I can find that even comes close is
from the Tree View Page of FreeCAD instructions. I know there's prob'ly scads of tips and the answer's prob'ly painfully obvious, and many apologies for not finding it on my own, but, could you please tutor me in how to re-arrange the Document Tree?The tip can be changed by the user.
Thank you again forever.
OS: Windows 10 Version 2004
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.24276 (Git)
Build type: Release
Branch: releases/FreeCAD-0-19
Hash: a88db11e0a908f6e38f92bfc5187b13ebe470438
Python version: 3.8.6+
Qt version: 5.15.1
Coin version: 4.0.1
OCC version: 7.5.0
Locale: English/United States (en_US)