Sketch copy and paste looses constraints

[pavmed]

Hi!

From Fusion 360 blog I know that there's nice feature - sketch copy and paste between designs.

Howether some testing shows that it looses some (?) constraints while copying.

This is source. Note black lines, their corned point has Coincident constraint with Origin

And this is copy. Corner point is not constrained any more. It's not visualisation bug as it can be moved freely.

Is this bug/feature?

[paul.clauss · Accepted solution]

Hi @pavmed

Thanks for posting! I believe this is working as intended - I received the same results as you. The angular and horizontal dimensions/constraints are maintained because they refer to either copied geometry or an axis parallel to the origin axes of the model. I think when the sketch is copied into a new file, the point from the original file used in the coincident constraint does not exist anymore and Fusion does not infer that it should replace that point with the sketch origin in the new file.

An example of this is shown in the screencast below. The coincident constraints referencing the copied geometry are maintained, but the coincident constraint to the sketch origin is lost.

I found that this also works the same way when copying sketch entities in a single file - the expected behavior is that copied entities may be moved (and are already copied to a new location), so constraints locking down a specific point of copied sketches are removed during the copy/paste operation.

Hopefully this helps! Please let me know if you have any questions.

[pavmed]

Hi Paul!

Thank you for your answer. That seems reasonable for me.

Howether there's still exists small bug (I believe it is): constraints icons are not visible in copied sketch unless one stops the sketch and reopens it again - then it's all in place.

[paul.clauss]

Hi @pavmed

Thanks for the response! I looked into the small bug and found that it does not seem to be occurring on my system - the constraints (apart from the coincident constraint to the origin) are shown immediately when I copy and paste the sketch in. This is shown in the gif below.

Are you certain that you have the "Show Constraints" flag enabled in the Sketch Palette? Hopefully this helps! Please let me know if you have any questions.

[pavmed]

Hmm,

Now I cannot reproduce it either.

Ok, thank you!

[tallisonUZUFP]

Okay, I get the logic of suppressing some constraints when copying and pasting sketches, but this gives me another problem. I have a design that has 5 concentric circles (and some related geometry) coincident on the origin. I want to reuse this sketch in a number of different sketches, as I develop multiple design solutions for the product I'm developing.

When I copy & paste this into a new sketch, the coincident constraint isn't copied, even though I'm clicking on the origin before I paste. After pasting, I have 27 sketch points, a sketch curve, 5 sketch dimensions a sketch geometry constraint and a profile, all at the origin and I can't find a quick or reliable way of re-applying the coincident constraints to all the important points. Specifically, selecting a circle centre and trying to make it coincident to the origin usually throws a 'sketch is over-constrained error', which is probably because I am trying to constrain it to another circle centre rather than the origin. 

Is there a quick way of constraining 1 circle centre to the origin in this situation?

When I first came across this 'disappearing constraints after copy & paste' issue, I wondered if there was another way of copying sketches. For example right clicking on the sketch in the browser window and choosing copy, then right clicking on another component in the browser and selecting paste. But this option doesn't exist. Curiously, holding down ctrl and left clicking/dragging a sketch in the browser from Component A, drags the sketch and puts a little + sign under it. When you hover over Component B the highlighting changes. So far so good. But dropping it on Component B doesn't copy it. It just seems to ignore the action. Maintaining all the constraints using these methods would be obvious.

So, I really do understand why you suppress 'global constraints' during copy & paste, but I cannot be the only person trying to reuse my previous sketches in their entirety. A second way that maintains all constraints during copy & paste is a biggy in my view.

[paul.clauss]

Hi @tallisonUZUFP

Thanks for posting! One way to do this is simply to drag the circles centerpoint to the origin when all the copied geometry is selected. This is shown below. If you'd like to see the option to include global constraints in copy/pasted sketches, please post on the Ideastation - we appreciate your input!

[tallisonUZUFP]

Thanks for your response Paul. The method you showed works for part of my sketch, but I just noticed that copy/paste doesn't copy the pattern function. For my sketch this means that the pasted version looks correct, but lacks the constraints that the original pattern function forced. Is this a bug, or is there a reason why the implicit constraints of a pattern are not copy/pasted?

[paul.clauss]

Hi @tallisonUZUFP

Thanks for posting! We do have some known issues with sketch geometry that should be copied not being transferred, but I am unsure of what the expected behavior with a pattern should be. I've reached out to the development team and will keep you updated as I learn more. For what its worth, pattern "constraints" are not copied on my end either at this time.

[pavmed]

Hi @tallisonUZUFP

I've developed two workflows to accomplish sketch reuse between models. Maybe some of this would help you too.

1. If sketch is intended to be reused then I DO NOT put it in the origin NEITHER apply any constraints between sketch geometry and origin. Instead I try to make sketch "self-sufficient", i.e. all constraints are made only between sketch explicit geometry. 

This contradicts best practices of using origin as "symmetry pole" and doesn't solve pattern issue, howether this makes sketch copyable. After copy/paste it could be constrained to the origin as well.

2. You can also make sketch or sketch set intended to be reused and export that to separate model. Then insert it as linked component into any other model and break link. This preserves all the sketch geometry and constraints and make sketch "copy".

All this should be considered as workarounds.

Hope this helps.

[tallisonUZUFP]

Hi @pavmed

Thanks for the workflows, both are sound approaches

Cheers

[hectorkal]

Hello,

Found this topic because i experienced the same problem ( sketch undifened after copy paste)

So i did what pavmed mentioned:

copy/pasted my sketch, saved it, closed fusion, reopened, -edit sketch,  defined now.

No idea how or why, sorry beginner here. 

For me this issue is solved now, just wanted to mention.