Sketch Equal Constraint Issues

[MattPerez314]

When sketching and setting Equal constraints between two lines everything works fine in most cases.  When I dimension one the second instance tends to flip direction or disappear.  This means I have to dimension before placing an equal constraint so it won't flip out.  To compound the issue more the response isn't consistent.  Some cases it will let me change the dimension and work, and others i will use the same dimension on the same sketch entity and it won't.

Example images.  

1. Draw the vertical lines, dimension 5mm and then add an equal constraint. - works fine.

2. Change the dimension to 4mm and the sketch flips out

3. On the "flipped out" sketch change it from 4mm to 6mm and it fixes itself

4. Undo back to the original 5mm and change it to 6mm and it flips out....(won't let me upload 4 but looks just like 2)

[jeff_strater]

Thanks, @MattPerez314, for reporting that.  I'll take a look.  Seems like a bug to me.  Personally, I tend to stay away from equal constraints, probably out of a Pavlovian reaction to stuff like this in the past.  I find it's easier to just add a second dimension, and make them equal by editing the second, and clicking on the first, so that the parameter of the first is used to force the second to be equal.  Yeah, it's a bit more work, but I tend to get better results.

But, I will report this to the solver folks.  Looks like a good case.

Jeff

[jeff_strater]

I have not been able to re-create this problem.  Can you share/post your design, so that we can investigate further?  Appreciate it.

Jeff

[Anonymous]

Thanks Jeff!  I can't share the file in question but i created a quick test that exhibits the same behaviors.  Just change the dimension and watch the magic 😉

http://a360.co/2in7Y5m

If you change the 25mm dimension to anything(say 30mm) the sketch flips out.  If you Undo and change it to 20mm it flips out.  While the sketch is broken change it from 20mm to 30mm and it works fine...

Thanks again!

Edit, Jeff apparently it logged me into my second Fusion account that i use for creating Design Academy videos.  Still the same person though 🙂

[jeff_strater]

Thanks, @MattPerez314 (and @Anonymous ).  Great job creating a simple case.  You should consider a job in CAD QA...

This bug has been filed as:  FUS-36811

Jeff

[MattPerez314]

Thanks Jeff!  I'll keep an eye out for this!

[novec001]

I'm experiencing the same thing, regardless of sketch or model complexity. Editing any dimension in a sketch with "Equal" constrained lines causes the constrained line to flip direction, even if the dimension doesn't change the length of the line in question. Removing length dimension on the line, or creating the dimension between connected lines instead of on the actual line, seems to fix the problem. I'll try to get a screencast together tomorrow.

I suspect it might be related to the overconstrain error we had when the "color by constrained" was in preview. When adding an equal constraint to lines that were originally drawn at the same length, the "Sketch geometry is over constrained" error pops up. Shortening the line by dragging an endpoint lets me add the equal constraint but results in the wonderful flip error.

[novec001]

Here's a screencast showing the overconstraint and flip problems, as well as my sometimes applicable workaround. 

[jeff_strater]

a follow-up:  Just heard from the dev team that this bug appears to be fixed on our current dev branch.  So, hopefully, the fix will make its way out to the world soon!

Jeff

[MattPerez314]

Thanks Jeff!  Sketching in generally has been pretty buggy this go round so hope the new push stabilizes it!

[Anonymous]

I'm having similar issues with sketch 4 on this design.

1) Lines flipping direction when something else is dimensioned - this you reported.

2) I'm also getting an overconstraint error which is obviously false, the lines are all blue and move around when dragged... See the (dimensions)

Could you check this out and report a bug please.

The sketching is quite frustrating at times... hope you could make it work better overall.

Thank you!

-J

[MattPerez314]

jaakko I have had the same over constrained issue as well.  Seems to pop up for me when I offset something, make edits to the original projected edges and it tends to lose its dimension.  When I re-dimension there are several lines that are blue, free to drag around but throw an error when trying to dimension them.  

[Anonymous]

How can you say that? You stay away from cad if you do not use equal constrains!!!

It is mid May 2019 and this is still the case as described above!

I was intending to move my cad system to Fusion but guess what ...

[Anonymous]

No, the bug is still there and now it's 2020!

I'm running 2.0.7046

This needs to be fixed.

Sören

[TrippyLighting]

Please post a design with such a sketch and perhaps create a screencast.

[Anonymous]

Here you go.

This is my first post so let me know if the screencast and file was ok.

[Anonymous]

Same Problem here.

[davebYYPCU]

Not much wrong with the equals constraint, just the initial setting out was giving Fusion too many options.

Re arrange if my connections are incorrect.

Might help.....

[davebYYPCU]

Your looks to be the same problem, as the previous guy, lines will adjust their length, Fusion gets more than one right answer, has to pick one, we only complain when it comes out the wrong way.  

[Anonymous]

Hi,

I'm not sure what you did... Could you describe the steps please? Screencast maybe?

And no, Fusion changed the direction of the line (from positive to negative) so it's definitely a bug.

And no other CAD program I've used have problems with this.

I've found issues with other constraint types too in Fusion.

Regards

Sören