topic Re: Help with constraints in Fusion Design, Validate & Document Forum

Help with constraints

StephenCim-001 — Sat, 21 Oct 2017 10:01:51 GMT

Hi All

Sorry if this is a basic question but something is not working has expected

Please take a look at this. I placed a 10mm circle on Top plane, then offset the top plane -4mm, place a 7mm circle on it

Then added a sketch on the from plane, intersected both circles , then placed a line between intersect points. since the line is black it should be well defined.

I then I thought if I change the diameter of the bottom circle from 7mm to 6mm , the line would remain connected to the intersect point.

The intersect point moved , but the line on the point did not move with it.

Am I expecting to much?

Cheers, Stephen

Re: Help with constraints

SaeedHamza — Sat, 21 Oct 2017 10:56:20 GMT

Hi,

Constrains can't be applied between different sketches, especially when they are vertical to each other like your case

what exactly are you trying to achieve?

Regards

Re: Help with constraints

StephenCim-001 — Sat, 21 Oct 2017 12:02:03 GMT

Hi Here is another screen shot.

It's the same design has above , In sketch on the the XZ Plane I mirror the line to the other side .

The on the YZ plane I added a sketch , used the same process, first intersect the top and bottom circles, then added the line on 1 side and mirrored it to the other side

Then I resized the top circle from 9mm to 10 and the bottom circle from 7mm to 4 mm, The pair of lines on the YZ plane maintained their contact with the circles but the line in the XZ did not.

I'm quite confused 🙂

Re: Help with constraints

jeff_strater — Sat, 21 Oct 2017 12:43:57 GMT

Hi @StephenCim-001.

You've found the solution. The difference between your first and second versions is that the second had points on the circles for you to connect to. That's the key. If you have those points, everything will update.

The underlying reason is simple, but has to do with some stuff that we just never implemented. For a 3D line, Fusion supports point-to-point coincident constraints, but not point-to-curve. So, just adding the points on both circles will make it update correctly. Here is a screencast:

Hope this helps,

Jeff

Re: Help with constraints

StephenCim-001 — Sat, 21 Oct 2017 13:09:25 GMT

Hi,

I thought I was creating point by Selecting 'Project/Include -> Intersect , to create the small red points,

OK, here ate the steps I used , added Large circle to XY plane, offset XY -6mm

Added sketch to XZ plane

Project->Intersect both circles, end up with 2 red points from each circle, I then turned off the Circle sketches

And added 2 lines using the intersect points, Then repeated the process for YZ Plane, to get below.

Now look what happens when I resize the Circles. One Sketch works fine the other looses it's point-to-point coincident constraints between the line point and the red intersect points.

Should I not use Project Intersect points?

Cheers, Stephen

Re: Help with constraints

jeff_strater — Sat, 21 Oct 2017 15:31:00 GMT

OK, there may be a bug with Project Intersect here then. Let me investigate. Thanks for adding the details, that helps a lot

Re: Help with constraints

StephenCim-001 — Sat, 21 Oct 2017 22:52:50 GMT

Just thought I should mention, I running the latest Fusion release on MacOS High Sierra (10.13)

Re: Help with constraints

laughingcreek — Sun, 22 Oct 2017 00:13:10 GMT

What you are experiancing is a BUG that I have come up against before. I'm pretty sure I've seen it reported as a bug to AD also. When I repeat what your doing using intersect to produce the dots, I get the same behaviour on the ZX plane, but the project points on the ZY plane stay properly connected.

The work around i used before is to draw construction lines between the points on the circles where I will need to attach the connecting lines (in this case through the center of the circle at the quadrants). You can draw your new lines between these construction line endpoints, and they will stay constrained when you resize the circles. (no need to project first)

Re: Help with constraints

StephenCim-001 — Sun, 22 Oct 2017 08:46:49 GMT

Hi All

I think I have something working 🙂

Here is my bezel, current setup for a 12mm round stone

Now resize stone to 10mm

Change the diameter of the bezel bottom

Now nudge the prongs out a bit so the cover less of the stone

make the bezel longer and larger gap between top and bottom sections

Or make it a full bezel 😉

Re: Help with constraints

jeff_strater — Sun, 22 Oct 2017 20:36:06 GMT

Yes, this has been filed as FUS-36562, and is a bug with circles and Project -> Intersect. For some reason, this reference is not updated correctly when the circle changes size. I will see about elevating this a bit in priority.

jeff

Re: Help with constraints

jeff_strater — Fri, 10 Nov 2017 15:43:55 GMT

follow-up on this issue: I just got a report from the dev team that this bug has been fixed on our latest development build. It will take a bit for it to percolate out to the real world, but wanted to let you know that this one had been fixed.

Jeff

Re: Help with constraints

laughingcreek — Fri, 10 Nov 2017 15:54:14 GMT

That's great news. this bug was causing lots of frustration.

Re: Help with constraints

StephenCim-001 — Fri, 10 Nov 2017 23:01:55 GMT

Thanks 🙂