3D Sketch won't fully constrain

[stoltenkamp.scott]

Hello all.

I can't seem to constrain my 3D sketch to fully define it.

It's a simple tetrahedron with vertex points constructed equidistant from the origin.

The sketch was done from the right plane so that way the front edge would lay on the YZ plane.

There is only 1 dimension and the rest of the construction is done with constraints.

My question is this expected behavior or did I screw something up?

I can't seem to create any additional constraints or dimensions as I get over constrained warning or reference dimension option on any angle or length I try to place.

[TrippyLighting]

The constraint solver code for checking if something is fully constrained does not work 100% reliable for 3D sketches.

I don't know exactly what your design intent is, but this does not require a 3D sketch.

I would only use 3D sketches where there is no alternative.  

[stoltenkamp.scott]

☺ edit.. replied to wrong post.. see next

[stoltenkamp.scott]

No design intent behind this just checking on progress more than anything.

This is based off an old pre-employment test at a big tech company using that other parametric modeling program.

The test was to complete the tetrahedron with COM @ model origin as quickly as you could while keeping it "tight." The person who gave me the test parameters had never seen anyone use only 1 sketch, no construction planes and only 1 dimension. We had a pretty lengthy discussion about the feature afterward while waiting for the others to finish. Their evaluators didn't score it well, they were looking for specific things i hadn't incorporated since no construction geometry was necessary. The only thing i got credit for was COM. They didn't even give me credit for the loft since they didn't understand where the second sketch was that I was lofting to was.

[TrippyLighting]

What progress ?

What does the term "COM" refer to ? 

[stoltenkamp.scott]

When I said progress I was referring to the living breathing animal that Fusion is.

COM = Center of Mass.

[RyanCameron]

It's possible that the over-constrained warning is indicating that the sketch is fully defined and cannot accept any additional constraints. This would mean that the tetrahedron has been completely constrained by the one dimension and the other constraints you have applied.

If you are still able to manipulate the sketch, you can try dragging one of the points and see if the tetrahedron remains intact, which would confirm that it is fully defined. If it is not fully defined, then you may need to add additional constraints to fully define the sketch.

One thing to check is whether any constraints are conflicting with each other. This can sometimes cause issues with fully defining a sketch. You can check for conflicting constraints by looking for constraints that are highlighted in red or by hovering over the constraint icons to see if any warnings appear.

If you are still having trouble fully defining the sketch, you can try deleting some of the existing constraints and reapplying them in a different order. This can sometimes help to resolve over-constrained or conflicting constraints.

[TheCADWhisperer]

@RyanCameron 

Can you get the sketch to show as fully defined?

[RyanCameron]

It's not my question or sketch..  ?...

[stoltenkamp.scott]

I've added a second sketch to highlight the difference when I didn't force my construction lines to reside on the right plane. In this sketch the Move command on the lower 3 sketch points will still let you rotate the tetrahedron.

@RyanCameron,

I can't seem to modify it in any appreciable way to get the solver to recognize it as fully defined. I've been over it a few times checking to see what I may have missed and I couldn't find anything. I can't reposition any of the sketch points by dragging them or with the move command. I've trashed and reapplied the constraints numerous times with no success getting it "solved."

@TheCADWhisperer

Did you have any luck finding what I may have missed or do you concur with @TrippyLighting that the solver just gets a bit wonky with the 3D Sketch function and sometimes fails to resolve?

[TrippyLighting · Accepted solution]

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@stoltenkamp.scott wrote:

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@TheCADWhisperer

Did you have any luck finding what I may have missed or do you concur with @TrippyLighting that the solver just gets a bit wonky with the 3D Sketch function and sometimes fails to resolve?

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Just to avoid confusion, what the sketch engine is failing to do is recognizing whether or not the sketch is fully constrained. The constraints themselves work as intended.

I would say that on average I look at at about 1-2 Forum user designs a day, every day. I prior years that has often been 4-5, so I've seen many thousands of designs by other users. It is not so unusual to see a 2D sketch that is fully constrained but not recognized as such. 

The sketch solver is certainly getting better in recognizing fully constraint situations, but it isn't at 100% yet.

[stoltenkamp.scott]

@TrippyLighting

I appreciate the input.

Tangentially... it doesn't spear that you can use constraints with construction geometry. Things like arc tangent to plane, point coincident with plane, line perpendicular to plane, etc.

My search results came up with a couple topics from 2020 that indicated it was an upcoming feature. Any idea where I could go to track progress on that?

[TrippyLighting]

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@stoltenkamp.scott wrote:
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Any idea where I could go to track progress on that?

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No, unfortunately not!

[stoltenkamp.scott]

KK thank you!

[RyanCameron]

Good to know!