topic Bug, Can't create constraint over a Control Point Spline in Fusion Support Forum

Bug, Can't create constraint over a Control Point Spline

zmpXSM6L — Wed, 05 Feb 2020 16:19:38 GMT

Hi, I created a simple Control Point Spline, than I Fix it .

Than i Created two perpendicular lines , one connected to the Spline

When I try to create a constraint between point "A" and point "B"

Fusion says it's overconstrained. But it's not!

Those two perpendicular lines should be moving along the Spline freely without the constraint,

It does actually move but with some trouble.

When using a Fit Point Spline this works fine!

Re: Bug, Can't create constraint over a Control Point Spline

JamieGilchrist — Wed, 05 Feb 2020 18:24:40 GMT

hi zmpXSM6L,

your spline is green, which means it has been locked. Select the spline and unlock it and see if that resolves the over-constrained error.

Re: Bug, Can't create constraint over a Control Point Spline

zmpXSM6L — Thu, 06 Feb 2020 02:25:22 GMT

Hi, yes it's locked and that's the way it should be.

If I turn the lock off, it will not throw an overconstrained error anymore, but it will move the entire spline as I change the dimension constraint, and that's not the behavior I expect.

As I said, it works fine with a Fit Point Spline

The two perpendicular lines move along the path of the spline.

If I create the constrain before locking the spline an than I lock the spline I can't change the constraint, it throws an error "Fail to Solve"

Re: Bug, Can't create constraint over a Control Point Spline

jeff_strater — Thu, 06 Feb 2020 15:02:40 GMT

@zmpXSM6L - this looks like a bug to me. I will try to re-create it, but if you want to share your design here, I can make sure that this case gets attention. Thanks for posting.

[edit] Actually, I had similar problems with a fit point spline. In both cases I could drag the line construct a bit, but it would soon stop. And, in both cases, if I tried to create, say, a horizontal constraint with the endpoint of the line and one of the locked spline points, I got an overconstrained error. So, if you can share your design, and show a video of it working for fit point splines and not for CV splines, that would be very helpful

Re: Bug, Can't create constraint over a Control Point Spline

jeff_strater — Fri, 07 Feb 2020 01:20:54 GMT

I can reproduce the issue on my end, but it seems to happen equally for fit point and CV splines. I've created bug FUS-60631 to track this.

Re: Bug, Can't create constraint over a Control Point Spline

zmpXSM6L — Fri, 07 Feb 2020 13:55:01 GMT

Hi Jeff, I have recorded an screencast describing both behavior(the right and the wrong)

Re: Bug, Can't create constraint over a Control Point Spline

jeff_strater — Fri, 07 Feb 2020 18:17:41 GMT

Thanks. One thing I discovered while creating the bug is that the culprit seems to be the horizontal constraint on the line that connects to the spline. In both cases, the drag works if I remove the horizontal, and is glitchy, at best, with the horizontal applied. I tested with closed splines, not sure if that makes a difference or not.

Re: Bug, Can't create constraint over a Control Point Spline

zmpXSM6L — Sat, 08 Feb 2020 03:31:05 GMT

For me a Closed Spline no Matter which type causes the same bug. Only a open Fit Point Spline works as expected