topic Re: Nested Polygon Constraint Issue in Fusion Support Forum

Nested Polygon Constraint Issue

Anonymous — Thu, 06 Aug 2020 20:53:32 GMT

I'm running in to issues with constraining a series of nested hexagons that I'm trying to uses as the bases for loft profiles. I'm starting with the inner most hexagon, defining it with a circumferential radius and defining one side as horizontal/vertical . For all other 'outer' hexagons in the nest, I'm constraining one side as horizontal/vertical and coincident to the intersecting corner of the 'inner' hexagon below. This appears to work fine for the first 3 or 4 hexagons but fails to fully constrain any additional hexagons (as shown below). My attempts to further constrain the hexagons fails with an over constrained error. I also don't appear to alter or move any of the non-constrained sides as the program returns an over-constrained error even though visually it indicates the lines are not fully constrained.

I believe this issues is causing issues with my lofting profiles starting which works for the constrained hexagons but runs in to problems at the first non-constrained hexagon. It is behaving similarly to a non-closed profile error that I've run in to the past, with fusion creating 1 additional node point (beyond the 6 corners of the hexagon) at the mid point of one of the hexagon sides. To create the lofting profiles, I'm projecting one of the hexagons onto a new sketch on an offset plane and offsetting the projected hexagon to form a shell.

Re: Nested Polygon Constraint Issue

Anonymous — Thu, 06 Aug 2020 21:18:17 GMT

Quick update. I found a work around by creating a parameter for each hexagon radius with the radius set as a function of the radius of the inset hexagon and using the horiz/vert constraint. This creates fully constrained nested polygons but my original issue still seems like a bug.

Re: Nested Polygon Constraint Issue

davebYYPCU — Thu, 06 Aug 2020 21:19:04 GMT

So sketches on the Offset Planes are partial projections from this ... sketch.

Blue polygons may not be coincident to the origin. Click drag them

Try projecting one anchor point to each plane and create the polygon where it is needed.

Might help....

Re: Nested Polygon Constraint Issue

jeff_strater — Thu, 06 Aug 2020 21:48:08 GMT

I was able to get this by projecting just one line from the sketch below into the sketch above, then using inscribed polygon:

Re: Nested Polygon Constraint Issue

jeff_strater — Thu, 06 Aug 2020 21:50:55 GMT

sorry, hit Post too early. Then, I tried to do the loft, and the point mapping gets all screwed up. I had to add all 6 rail curves to get it to work:

and this produces what I suspect is your goal:

model is attached

Re: Nested Polygon Constraint Issue

Anonymous — Thu, 06 Aug 2020 21:57:15 GMT

Yes...sketches on the offset plane would be projects of the original sketch containing all nested hexagons. The photo below is my work around by defining the circumscribed radius of all hexagons as a function of the inset hexagon and shows the base sketch and partial projections of individual hexagons onto the offset planes.

Re: Nested Polygon Constraint Issue

Anonymous — Thu, 06 Aug 2020 22:03:56 GMT

Yes my goal was something similar (see below). I found a work around by defining the circumsribed radi as a function of the inset hexagon...but it still seems like there is some bug in my original solution with constraint relationship breaking down.

Re: Nested Polygon Constraint Issue

Anonymous — Thu, 06 Aug 2020 22:20:49 GMT

Hmmm more interesting results. So I was able to get the horiz/vertical + coincident constraint relationship to work in a new design (actually it was the second new design after a program restart) but it is still failing to compute(?) in my original design.

New Design

Original Design - New sketch only partially constrained outer hexagon

Re: Nested Polygon Constraint Issue

jeff_strater — Thu, 06 Aug 2020 22:47:45 GMT

you'll have to share your design here to get more information - I can't tell from just the screen shots what is happening.

Re: Nested Polygon Constraint Issue

davebYYPCU — Thu, 06 Aug 2020 23:15:03 GMT

Jeff’s first pic, makes more sense to me, than you struggling with a bug.

Fusion works better when sketches are less complicated.

Might help....