Unfortunately, that's one of the worst weaknesses of FreeCAD, inherent to the OCC geometric kernel, and it is known here as the topological naming issue. It's been mentioned countless times on the forum, a few programmers have attempted to tackle this problem over the years, but it's a complex one.OakLD wrote: ↑Sun Feb 18, 2018 3:03 pmOne would expect, that the face in which the pocket is hosted would keep it's ID, but looking into Constraint details and comparing it with what I see when I select the faces in "Selection View", I see that the face got a new name. When I modify the face name in the constraint (thanks to the this forum for a solution) to what I see in Selection View (i.e. Face12 instead Face33), the constraint resurects and the part takes it's correct position in the constrained direction.
EDIT: What's worse, ALL the faces of modified part get different name, even those left untached by any changes.
In short. No. When you create parent <-> child relationship and you change topology (number of for example faces) of the parent. You usually need to redefine the relationship after.1) Are there any tricks or workarounds to avoid such troubles?
2) Are there any tools or procedures to repair broken contraints?
3) Is there any tool or command to purge unused constraints (left after deleting a part instance)?
Well, let's be honest, that even though there are some ocasional glitches in most major 3D CADs, even those based on the newest parasolid, which they promised would be "flawless", there are no problems with the common stuff like a change of constraint dimension or an extra pocket. But the claim about the army of programmers is true, there's a lot of investments by Siemens or Dassault or such into 3D CAD/CAMs. Though, 5 good motivated programmers can do more than 100 employed to do the same job. In this sccope, the achievement of FreeCAD is really awsome already.On the other hand, I'm proficient with a commercial parametric CAD program which I use daily at my job, and it too suffers from this issue, albeit to a lesser extent. Since that commercial program no doubt benefits from an army of full-time paid programmers
I did have a look, but it doesn't work at all, or I don't use it correctly. When I apply "Plane alignment" constraint, I can see new entries in the new Assembly tree within "Constraints" and "Elements" nodes, but the parts refuse to react in any way to the applied constraints. I couldn't find any information about current state of Assembly 3, so I asumed it could as well be in very early development stage.
Well, I'm ipressed anyway . I've been glancing at the project for many years and when I tested it now after another few years, I was positively shocked at how far the project got.triplus wrote: ↑Mon Feb 19, 2018 1:45 pmChanging constraint value is in general OK. Going back in design history to add an additional pocket changes topology. Assembly relations fur such part therefore will likely need to be redefined after. That is correct yes. Note that once FreeCAD will have some (history based) topology/geometry solution tackling this area. Things will likely improve. As for some thinking and planning ahead when using a parametric CAD. Yes you correctly identified this too. It's called design intent.
P.S. But as said it gets better with experience.
https://github.com/realthunder/FreeCAD_ ... /Readme.mdOakLD wrote: ↑Mon Feb 19, 2018 2:23 pmI did have a look, but it doesn't work at all, or I don't use it correctly. When I apply "Plane alignment" constraint, I can see new entries in the new Assembly tree within "Constraints" and "Elements" nodes, but the parts refuse to react in any way to the applied constraints. I couldn't find any information about current state of Assembly 3, so I asumed it could as well be in very early development stage.
That Plane relation in Assembly 3 is a tricky one indeed. I tend to avoid it for now. Hopefully it will improve a bit over time. Create Assembly feature and drag and drop two Part cubes in it. Select two points on Cubes edges and add PointCoincidence relation. If you have Auto recompute set to ON it should just work. If no press on Solve constraints command after. But note that Assembly 3 doesn't resolve the topology related behavior we discussed earlier.
Welcome to the club.Well, I'm ipressed anyway .
I would likely recommend exploring Arch workbench for such project. In Architecture fully parametric approach (like in mechanical engineering) usually isn't needed. Said that in FreeCAD Arch workbench offers a lot of parametric features. And you could design a house in Part Design. If that is what you would like to do.I decided to use FreeCAD for some home projects like a barn I will be building this season, as an alternative to SketchUp (free version without LayOut) I'm used to.