Sketch Constraints aren't permanent

[Nailerish]

For the past couple of weeks I've noticed Fusion acting weird. When drawing a sketch my geometry won't let me apply constraints to them (The geometry is not over-constrained). I will use the dimension tool then I will be able to select one of my lines but on the other. The same happens for the other constraints as well. I also will eventually add a constraint, but then when I apply another constraint the first one will disappear. In the attached screenshots I drew a 2 point rectangle that was constrained at one corner. I then applied a coincident constraint to the other corner and the horizontal verticle constraints disappeared creating a "not rectangle'.  If anyone knows whats going on please help. 

[davebYYPCU]

1st pic shows two black, one blue line, with a vertical constraint, and a profile.

2nd pick shows you moved the top left corner to the purple point, to get there, Fusion has  broken open the profile, and left the bottom line as it was.  You need more constraints to finish it up, but nothing to say things are right or wrong yet, from detail provided.

Might help....

[Nailerish]

The length of the rectangle hasn't been contained. It should simply keep it as a rectangle with all the verticle constraints and slide the left verticle line to the projected point as it has done for the past couple of years.

I also can't add a constraint to the diagonal line shown in the second picture. After it becomes a diagonal line I can no longer select it at all or add any constraints. 

[davebYYPCU]

Yeah, well unless the purple point was not on the sketch plane, if your sketch is now a 3d sketch (not fully planar,) then thats expected behaviour.

Might help....

[Nailerish]

As you can see from my sketch pallette 3D sketches are disabled, and I've made sure it was totally planar. 

The expected behavior is to not delete preexisting constraints. If the geometry is over constrained I should get an error notification. If it is not overly constrained it should use the prexiseting constraint to calculate the new placement of the line as it usually does. There is no reason it would automatically delete a constraint to complete geometry.

[davebYYPCU]

If your Sketch is 3d, works just as you are complaining about, constraints and dimensions are deleted and won’t / don’t work as expected.

Ticked or not.....

Edit Sketch, Right Click, If you can select, Move to Sketch Plane, do so.

Might help....

[Nailerish]

I know it would, I've encountered that before. However, I have checked this sketch is totally planar, but it is still happening.

[jeff_strater]

if you share your design, we can check it out.  A simple test:  If you select one of these geometries, and right click, does the "Move to Sketch Plane" menu item appear?  If so, then that geometry is not already on the sketch plane.  Even if the geometry is planar with respect to itself, if it is not on the sketch plane, dimensions and constraints will be removed.

[GRSnyder · Accepted solution]

Of note, there seems to be a bug currently that results in some constraint indicators and dimensions disappearing from sketches even though they are still actually there and are enforced. For me, closing and reopening the sketch usually fixes this. I've been looking for a reproducible test case, but it's very sporadic.

[Nailerish]

I'll have to try that next time it pops up. Thank you.

[davebYYPCU]

But how is that bug relevant to this example, 

aligning a rectangle corner to a projected point, did not retain the vertical constraint, and broke the profile, making black lines turn blue?  

Surely the vertical constraint was deleted.

[Nailerish]

The bug he described sounds like what is happening. 

Constraints don't just delete themselves if you over constrain a sketch. An error will popup telling you that you've over constrained it. I've already told you multiple times that what you're saying does not apply to my issue. Unless you're going to add something constructive and new to the conversation please stop responding. 

[GRSnyder]

In this case, the fact that a rectangle turns into a not-rectangle is pretty good evidence that the Horizontal/Vertical constraint is genuinely gone. I just mentioned the disappearing notations bug because it's been happening pretty frequently to me and it complicates constraint debugging considerably if you don't realize it might be in play.

[laughingcreek]

So, your issue is a constraint becoming not visible, but still present and enforced?  (that's the bug @GRSnyder is describing)  It sounded like from your description you were losing a constraint.   I REALLY mis-understood your question.