All black sketch but not fully constrained.

[msecco]

Is this sketch fully constrained?

Hide constraints to clarify:

All lines are black, but:

Angle dimensions are missing:

Inventor exemples:

[g-andresen]

Hi,

please share your design to take a look.

günther

[msecco]

hI.

https://a360.co/2D6196m

[HughesTooling]

Here's what I get in my old copy of Alibre. I always liked their use of 3 colours for DOF feedback.

Mark

[msecco]

Hi @HughesTooling 

It is a very good idea.

I never liked this too:

[wmhazzard]

@msecco  In your case from what I was told by Autodesk, they consider a line constrained if it has two constraints on it, say starting at the origin and having a vertical or horizontal constraint on it. They do not consider the end point of the line part of the line so the length of the line has nothing to do with fully constraining the line. I, and I think many others find that ludicrous but that is the way it is. I think some of the sketch constraint problems relate back to that faulty logic.

[professor.secco]

And it is worse than I thought, the sketch icon also says that it is fully constrained when it is NOT!

[TrippyLighting]

After some experimentation, it looks to be the culprit is the mirror constraint.

Of course, mirroring an entire sketch is also not a recommended practice in any CAD software, but that might be beside the point.

 

[msecco]

@TrippyLighting Only Fusion 360 has this problem.

I tested (and asked to test) this with Inventor, Onshape, SolidWorks and @HughesTooling  tested with Alibre, all of them show the sketch not fully constrained, evem when mirrored.

@wmhazzard said, that for autodesk, a segment with two restrictions is considered constrained. When mirroring, a symmetry constraint is added at each point in the sketch. Thus, all segments are mistakenly considered restricted in Fusion 360.

If remains a single point with some degree of freedom, the sketch cannot be considered completely restricted.

[TrippyLighting]

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@msecco wrote:

@TrippyLighting Only Fusion 360 has this problem.

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Yep, no surprise. I don't mean that derogatory in any way. Fusion 360's sketch engine is very new compared to the sketch engines in other software packages.

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@msecco wrote:

If remains a single point with some degree of freedom, the sketch cannot be considered completely restricted.

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Agreed!