[SOLVED] Why is FreeCAD symmetry-stupid?
[SOLVED] Why is FreeCAD symmetry-stupid?
Maybe there's something I don't understand here. I'd love it if someone told me how to do the following.
Let's say I have some really complex shape in a sketch left of the Y axis: it takes me forever to get it just right. Then I need to mirror it on the right side of the Y axis and connect the two halves.
In SolidWorks, it's trivial: mirror the stuff, done. If you change the master shape on the left, the change is reflected on the right.
In FreeCAD, the best you can do is make a mirror copy of the left-hand side elements - which also makes copies of the constraints which are completely independent from the original constraints on the left-hand side - delete the stupid new right-hand side constraints and slowly, painfully constrain the right-hand side copies to the original left-hand side elements, trying to dodge the dreaded orange over-constraints all the time. It's long, it's painful, and the end-result is usually so fragile that if you change anything significant on the left-hand side, the sketch turns orange and then it's back to hunting broken constraints again.
Surely it can't be that painful. Am I missing something obvious?
You want Sketcher Symmetry but it's not quite what other CAD packages have. Select what you want to mirror, which is probably the entire sketch using the drag selection box, select the
Sketcher Symmetrytool, then pressJto add constraints.It's not perfect, I suspect because it can't read your mind as well as the big CAD packages about where you want coincident constraints for joining lines, but it's mostly OK.
EDIT: I can't tell if you are describing the Sketcher Symmetry tool in your 4th paragraph or not. You will sometimes get over constraints where the end points intersect but you can delete them with one click and make those points coincident instead. I suppose this could be time consuming if you have a really really complicated sketch with multiple intersecting points, but that probably wouldn't pad anyway.
I can’t tell if you are describing the Sketcher Symmetry tool in your 4th paragraph or not
That's the one.
It’s not perfect
It's much worse than that, is my point.
I suspect because it can’t read your mind as well as the big CAD packages
What mind reading is there to do? I want a symmetric verbatim copy of whatever I modeled on one side. I don't want constraints or anything in the mirror, just that it should match the original in reverse.
The fact that FreeCAD's symmetry tool even deals with additional constraints makes it dumber than a sack of bricks.
which also makes copies of the constraints which are completely independent from the original constraints on the left-hand side - delete the stupid new right-hand side constraints and slowly, painfully constrain the right-hand side copies to the original left-hand side elements
I feel like this is not how it works for me. It does copy the constraints and automatically create symmetry between any points across the selected center line, but if you're making a mirror why is that not what you want?
Also I'm unsure about the behavior in older versions of freecad, the constraint behavior of this feature is new in 1.0