Sketch rectangular pattern and constraints

[Anonymous]

This might be a simple question.  But why is it that when I make a rectangular patten from a fully constrained sketch, the result is an under constrained sketch?  Why does the "pattern" operation constrain all of the child objects?   The spacing of my patten is driven by other dimmensions, so the locations ought to be constrained.  Changes to either the driving dimmensions of the spacing or the coppied lines all seem to propagate as expected.    The only work around I've found is to select and "fix" elements of the sketch, but this seems to overconstrain the sketch in my opinion, as I have to undo this constraint to change any of the driving dimmensions without the solver complaining about not being able to find a solution.

Thanks.

   --- Carl

[jeff_strater · Accepted solution]

Hi @Anonymous,

You are correct.  Your sketch is fully constrained, but does not display that status correctly.  That's why this feature is still in the "Preview" category - we haven't yet worked out all the bugs, and pattern is one of those.

So, apologize for the misleading info, but rest assured that your sketch is, indeed, fully constrained, as you think it should be.

Jeff Strater (Fusion development)

[Anonymous]

Great!
Thanks.

[Anonymous]

Thanks for the info on constrants.  That's reasonable given that the feature is still in beta.

I've also observed that patterns seem to be VERY SLOW. Doing something like creating a honeycomb vent hole pattern, which can easilly have hundreds of openings, absolutely crawls.  Any hope of some performance improvements with patterns?

Thanks.

    --- Carl

[jeff_strater]

Yes, large sketch patterns are indeed slow.  I would recommend avoiding large sketch patterns, and instead using Feature pattern instead.

Here is another recent thread on this topic:  fusion-360-application-not-responding-anymore-reproducible.

See the video here for how to use Feature pattern to achieve similar results.

Jeff