topic Most components suppressed - but constraints are still active in Inventor Forum

Most components suppressed - but constraints are still active

WHolzwarth — Fri, 25 Nov 2016 15:49:50 GMT

Hmm. I've damaged a 1500 parts assembly.

Trying to find the bad constraints, I suppressed most components and wanted to unsuppress them step by step.

But their constraints are still active, and lock re-positioning of the components. See screenshot (red points).

Is there another way than suppressing the constraints manually, too, and re-activating them one after another?

Thanks for comments

Walter

Re: Most components suppressed - but constraints are still active

blair — Fri, 25 Nov 2016 17:43:25 GMT

You didn't post which version of Inventor you are on but the last number of releases have a "Show Sick Icon" function. It's in the "Contraint" panel and will change for greyed out to proper color when you have sick constraints.

It will then show which constraints are bad on the model.

Re: Most components suppressed - but constraints are still active

WHolzwarth — Fri, 25 Nov 2016 18:14:21 GMT

It happened with 2017. I changed several directed angles to explicit reference vector angles. All was looking good, but suddenly the model was placed with 180° degree rotated. I think, some of the changed angles turned to a new position after a rebuild.

I've seen some yellow marks in Relationships, but I can't change them without unlocking other constraints.

I think, I'll get that fixed later in the evening.

Thanks, Blair

Walter

Re: Most components suppressed - but constraints are still active

WHolzwarth — Fri, 25 Nov 2016 21:38:43 GMT

Most of the work is done now. I'll try to reproduce later with a simple sample, what happened.

Re: Most components suppressed - but constraints are still active

Sofia.Xanthopoulou — Tue, 29 Nov 2016 10:18:18 GMT

Hi @WHolzwarth,

much appreciated if you could post the reproducible steps.

I have seen that a lot that angle constraints act unpredictable. And honestly I am not always sure that I understand why....

Thanks a lot

Re: Most components suppressed - but constraints are still active

WHolzwarth — Tue, 29 Nov 2016 13:20:47 GMT

Here's a video about relationships between Directed angles and Explicit reference vector angles. I've used 30° angles. With non-zero angles it's obvious, but you won't see a difference with 0°.

Directed angles look the same in both cases, but reference vector types depend on the direction of the face, that's been used as reference. It's been hidden in my assembly for some time, but suddenly flipping came through.

Back to the topic:

- Many components are suppressed

- Their constraints are still active

- If some of them are bad, the assembly or it's components very often refuse to move to the new position

In this case, I had to suppress most of the constraints additionally, and re-activate them one by one.

Walter

Re: Most components suppressed - but constraints are still active

swalton — Tue, 29 Nov 2016 15:40:38 GMT

I believe you are seeing as-designed, expected behavior from Inventor.

To suppress a constraint, you have to select the constraint, not a component that uses that constraint.

Component suppression is a memory management technique. It allows you to remove the performance hit from complex parts, or high part count assemblies so you can focus your computer's resources on a sub-set of the assembly during the design process. Inventor retains the constraints so that the assembly will solve in a consistent manor with suppressed components.

Inventor solves the constraints in an assembly as a set of simultaneous equations. Each constraint can(will) affect every other constraint. The problem constraints may have a conflict with some other constraint in the assembly and you will need to troubleshoot each one individually. Suppress the problem constraints, then see what is broken in the assembly.

I find it very helpful build my constraint set in a consistent manner.

1. Ground the logical 1st component in an assembly at the origin.

2. 1st reference is the moving part, second reference is the fully constrained one.

3. Lock all component degrees of freedom before adding another component to the assembly.

4. Use constraints with limits to control motion when you need to drag with your mouse.

5. Use position reps to define critical motion for the assembly

6. Ground components and suppress their constraints if their location will not change.

Re: Most components suppressed - but constraints are still active

WHolzwarth — Tue, 29 Nov 2016 21:11:52 GMT

Thanks for your informative comments, swalton.

But IMO, Inventor still needs improvements with constraints, Posreps, and Studio animations.

I'm trying to move this car along a path, see screenshot.

I tried to do my very best with constraining in assembly environment, but Studio movements are an adventure. I've made lots of timeline moves in Studio, but I never got a full run. Timeline moves stopped at random times, I can't see, what's the cause.

Perhaps the 0.1s minimum step in timeline is involved.

Therefore I tried a video with image sequences of the full run. It's jumping, because I changed the view only by Spacepilot moves. But it came through.

Funny to see, what's happening with a few components. They do the run, but most of the components ran out of fuel ..

I can place the files for download, if needed.

Walter