Sketch Geometry Overconstrained

[rpagewood]

This has to be one of the most annoying features of F360. There doesn't seem to be any logic behind it and the message doesn't offer any indication of which constraints are causing the problem. Solidworks seems to offer a much more userfriendly solution when it comes to sketch constraints.

[innovatenate]

I've received that error myself, so I know exactly where you are at. Are you positive there is no underlying sketch geometry, projected sketch geometry, or a misunderstood constraint that is causing this issue? 

Is there any chance you could post a video or a sample file to this post? I would be happy to look at the video/file and see if I have any suggestions that may help.

Kind Regards,

[rpagewood · Accepted solution]

so it turns out that I had some of the sketch geometry fixed as well as being driven by constrains and dimensions. 

It would be nice if the pop up messages offered explainations rather than just giving a warning. I shouldn't need to come and post here everytime I can't figure something out.

[Anonymous]

So I'm hitting this too.

"Are you positive there is no underlying sketch geometry, projected sketch geometry, or a misunderstood constraint that is causing this issue?"

Well, in my case, I'm positive that I did do something wrong - probably many things.  How do I find out which one of them is causing the problem?  Is that error message really just "something's wrong, somewhere - good luck finding it!"  Surely it must log something that would help to track down the problem.

[TheCADWhisperer]

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@innovatenate wrote:

... a misunderstood constraint that is causing this issue?  

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Try changing the dimension in this sketch that controls the other dimensions (the largest construction circle diameter, I forget what diameter it is currently set to in this file, I think it should be d7).

Sometimes it works, sometimes it doesn't.

If I make the change in small increments rather than large increments, it is less likely to return error (I can eventually make large change through small steps).

[Anonymous]

Looks like I had the same issue. What the problem was I was doing a center arc and it already put in the R-6 dimension on the bottom flat part. If I wanted to add the a sketch dimension for the left flat part for clarity of what the scaled size is, then I have to delete the first dimension number.

[Anonymous]

Same here.  A clue as to what the program doesn't like would be nice.  I used Solidworks for about a year and I have to admit it was a lot more user friendly in that area.  

[Anonymous]

I often have the same problem and I agree about the level of frustration (plus time wasted) in trying to figure out what's causing the issue. I've been chasing one today for many hours and I'm pulling my hair out trying to figure out what's causing it.  ARRGH! I love Fusion 360 but this is painful!

John

PS. Here's a screenshot of my current issue:

[chrisplyler]

@Anonymous

If you dimension a rectangle BEFORE you put the Fix constraint on it, okay no problem. Actually, that dimension should turn into a driven one when you Fix the rectangle.

If you dimension a rectangle AFTER you put the Fix constraint on it, then of course it will be a driven constraint.

[Anonymous]

Hi, thanks for the reply!

Where have I used a Fixed constraint? If you spot one, please let me know! I would really like to figure out what I'm doing wrong.

When I said I set the value, I set the value equal to the global parameter "Height" when I created the rectangle. As you can see in the picture, the "Width" dimension, as shown across the bottom is still tied to that parameter (fx:whatever) but the one on the right has somehow become fixed / driven as evidenced by the (30.00). Incidently, '30.00' was the original value of the "Height" parameter.

John

[chrisplyler]

I can tell the Fix constraint has been applied to the rectangle because it is green.

[Anonymous]

Okay, apologies for my being dense... why is one leg (the width) NOT constrained (fixed) and the height is? I'm willing to agree that you are correct but I don't understand how the rectangle could be "fixed" but only one side is fixed and not the other? And more to the point, if the rectangle has been "fixed", how do I unfix it?

[chrisplyler]

Probably you drew the rectangle and dimensioned both sides when you created it, or soon afterwards at least.

Later, you Fixed it.

And later still, you deleted that dimension and recreated it.

You can UN-fix something by selecting it, and then toggling the Fix/Unfix constraint on the sketch options palette.

[Anonymous]

THANK YOU !!!!! 🙂 🙂 🙂

I figured it out just after your last email, but you are 100% correct. That did it. I never noticed anything turning green before, but that was definitely the problem.

MANY THANKS!!!

John

[thebirdman]

New to all of this, but doing well with lotz of practice.

Know this is an old thread but was having same issue, found also if you took what 360 was thinking you wanted for a dimension and just hit enter, the error would appear, if you instead entered the figure all was well?

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@rpagewood wrote:

This has to be one of the most annoying features of F360. There doesn't seem to be any logic behind it and the message doesn't offer any indication of which constraints are causing the problem. Solidworks seems to offer a much more userfriendly solution when it comes to sketch constraints.

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[Anonymous]

my solution ended up being as simple as deleting the construction line and remake it. Then it worked! 

edit: didn't realise how old this post was. Problem still happens sometimes and honestly the popup message in 360 is still the same and of no help!

[mts195898]

I have had a few of these , and being a total beginner need all the help there is . When that is all the info you get it don't help a lot 👍