This is something that's been annoying me greatly in 2013. I'm not sure if it's a bug or a feature, but either way I really wish it would just stop.
Take a look at the picture I've attached.
The face on the right side outlined in green is the plane on which my sketch was defined. I projected that face as construction geometry, and projected another edge as construction geometry over toward the left as well.
The purple square is a 2-point rectangle. I applied co-linear constraints between the top and bottom edges of the rectangle and the projected face, and an equal constraint between the lower edges, then the dimension of 1.250 between the inside edge and the projected line. The sketch is fully constrained.
The issue I'm having is that when I applied the co-linear constraints, they didn't go to the existing already projected construction geometry. They went to the edges instead of the curves, and those edges were then projected as non-construction geometry. This doesn't happen in a predictable fashion - sometimes it does it, sometimes it doesn't, but once it starts happening in a sketch, it will continue happening in that sketch forever and ever, even if I reboot the computer and start Inventor again, and I'm pretty sure it'll happen even if I save that part and open it on a different machine.
Now, in this particular instance it doesn't really affect anything other than offending my sense of propriety and my OCD about clean geometry, but there's other times when it HAS been a major issue. If, for instance, I'd projected that face and had the edges be non-construction geometry, and I was using coincident constraints to attach some new geometry to that, I could easily wind up with one end of something connected to the already projected edge and the other connected to a newly projected edge, and that will give me an open loop instead of a closed profile, and it's really annoying to track down each and every place that happens. (Of course, I could always do select other every single time I lay down a constraint but that's just as - if not even more - annoying.
Anyone have any ideas why this is happening?
Also, bonus question: I know that when you want to lay down sketch geometry with no automatic constraints, you're supposed to hold down control while you click and add your line segments. Thing is, why doesn't Inventor realize this? I've tried it with left and right control keys on three different keyboards, the control key on my Spacepilot Pro, and I've even mapped Ctrl to a mouse button just to try something different. Doesn't matter. I keep getting parallel and perpendicular constraints when I sketch. Just to make it even more interesting, I've got Inventor set to do horizontal and vertical by default, not parallel and perpendicular. Any idea what's going on here?
Nothing? Nobody else has this happen? Nobody has any workarounds?