topic Re: I can't preview my Assembly constrains in Inventor Forum

I can't preview my Assembly constrains

Anonymous — Tue, 09 Jun 2020 17:25:19 GMT

I don't know why the constrains preview isn't working. Out of nowhere these preview stop working. I've already checked the "Show Preview" option in "Place Constraint" window and it still doesn't work.

I also checked all options on the Assembly settings on the "Application Options". "Defer update" is off and "Enable relationship redundancy analysis" is off too.

I don't know how to fix this problem.

Re: I can't preview my Assembly constrains

Cadmanto — Tue, 09 Jun 2020 18:12:19 GMT

Welcome to the forum.

If it worked before just recently and now it doesn't. Have you tried restarting your PC/Inventor recently?

I have seen this simple action fix a lot of problems. 😉

Windows 10 x64 -16GB Ram
Intel i7-6700 @ 3.41ghz
nVidia GTS 250 - 1 GB
Inventor Pro 2020

Re: I can't preview my Assembly constrains

Anonymous — Tue, 09 Jun 2020 18:45:19 GMT

Hi,

Thanks for the response. I tried it but still doesn't work 😞

I don't know what did I disable, but out of nowhere it stop working.

Re: I can't preview my Assembly constrains

Cadmanto — Tue, 09 Jun 2020 18:52:56 GMT

It was worth a try.

See if you have below checked under the tools>options. Having this checked prevents the assembly constraints preview from working.

Windows 10 x64 -16GB Ram
Intel i7-6700 @ 3.41ghz
nVidia GTS 250 - 1 GB
Inventor Pro 2020

Re: I can't preview my Assembly constrains

JDMather — Tue, 09 Jun 2020 19:15:21 GMT

It took me a while to set up a scenario where I could reproduce same behavior (not sure if it is the same issue though).

First, you have Show Preview checkmarked in Constraint.

*Second, it is normal to have selection filter on Component or Part Priority in assembly.

Third, if I go to Tools>Application Options>Colors tab an turn off Enable Prehighlight, then I can reproduce behavior.

___________________________________________________

*Second - but if I set selection priority to Faces and Edges it works.

So if this is the issue, you have two choices.

Set your Selection Priority to Faces and Edges

Enable Prehighlight.

I didn't notice before that this can also be toggled in the Selection Filters (Shift Right Click).

Re: I can't preview my Assembly constrains

Anonymous — Tue, 09 Jun 2020 19:19:07 GMT

Yeesss, thanks it was that.

I had Prehighlight disabled.

Now it works good.

Thank you very much.

Re: I can't preview my Assembly constrains

johnsonshiue — Tue, 09 Jun 2020 21:28:50 GMT

Hi! Assembly constraint preview is disabled when one of the selected components is either adaptive or derived. It is because the preview cannot be properly created when component geometry changes due to adaptive or derive.

Many thanks!

Re: I can't preview my Assembly constrains

lena.talkhina — Wed, 10 Jun 2020 14:17:57 GMT

Welcome to the Autodesk Community!

Great to see you here on Inventor Forum.

Don't hesitate to accept a solution if you find one.

Re: I can't preview my Assembly constrains

andy_mullen — Thu, 20 Apr 2023 19:59:45 GMT

I am having the same preview issue. I tried the solution above by changing my selection to priority to faces and edges. My highlight check boxes and preview check boxes were already checked. I also check the previous Defer update suggestion and that check box is unchecked.

Re: I can't preview my Assembly constrains

JDMather — Thu, 20 Apr 2023 20:37:33 GMT

@andy_mullen

Can you Attach an assembly that exhibits this behavior?

Re: I can't preview my Assembly constrains

johnsonshiue — Fri, 21 Apr 2023 00:23:03 GMT

Hi! Two possibilities. One of the selected components is either adaptive or derived (iPart member). This is a legacy behavior. The preview cannot properly show the end result due to the need to update the part geometry also. As a result, the preview is disabled.

Many thanks!

Re: I can't preview my Assembly constrains

paulmWABYD — Fri, 21 Jul 2023 15:20:36 GMT

Hello all, I'm having the same issue. "Show preview" is enabled, "defer update" is disabled, and "prehighlight" is enabled. Selection filter is typically on component priority. I've attached an assembly and a screen recording of me attempting to mate in that assembly. As you can see, the first mate offers a preview, and the second two do not. This has been persistent almost since the first day I started using 2023. Roughly 90-95% of my constraints do not preview. This is very challenging when trying to ascertain which side of a plane is the correct normal, etc. I very frequently have to close the constraint window and reverse the orientation of my last constraint.

Apologies for the lack of constraint window in the recording; Windows' built-in screen recorder can only record one window at a time.

Re: I can't preview my Assembly constrains

ethanfL67BY — Mon, 09 Jun 2025 18:27:03 GMT

Yeah, I'm having the same problem. None of my parts are adaptive either. It's frustrating.

Re: I can't preview my Assembly constrains

johnsonshiue — Mon, 09 Jun 2025 22:12:20 GMT

Hi Ethan,

Likely, the parts are derived parts or iParts. Please share an example here so that we can confirm. Or send the files in zip to me directly at johnson.shiue@autodesk.com. I would like to understand the behavior better.

Many thanks!

Re: I can't preview my Assembly constrains

ethanfL67BY — Tue, 10 Jun 2025 12:32:16 GMT

Thanks for the reply. Once I run into an example I'll send a pack-n-go it over to you. The reasoning for the preview not working on my assembly is that I'm trying to make an adaptive part. But I think I have run into it not previewing before, but I can't remember what project I was working on.

Out of curiosity, how does it work with frame generator parts? Is it supposed to preview for those?

Re: I can't preview my Assembly constrains

johnsonshiue — Tue, 10 Jun 2025 18:31:31 GMT

Hi Ethan,

As long as it is not an adaptive part or a derive part, the assembly preview should work. Another possibility is that there is a preexisting failed constraint associated with the part you are trying to constrain. Please share an example that illustrates the behavior. There should be a logical explanation to the behavior.

Many thanks!

Re: I can't preview my Assembly constrains

ethanfL67BY — Thu, 12 Feb 2026 16:42:45 GMT

@johnsonshiue,

Hello Johnson,

I didn't find one where the constraint preview was broken but I did find one where a part is unable to be moved after putting in one constraint. I thought it was a simmilar problem. In this example we are working in assembly 0005473405 and we are trying to constrain part 0005474118. We have one mate on it and it now can't move for some reason. It is only constraining one set of planes together. However we can't move it in the "general" y or x direction as expected. Do you know why it is behaving like this?

Ethan Foss

Re: I can't preview my Assembly constrains

johnsonshiue — Thu, 12 Feb 2026 22:44:20 GMT

Hi Ethan,

Many thanks for sharing the files! I took a quick look and verified the behavior. Indeed, 0005474118 does seem locked up for no apparent reason. DOF analysis shows there are three degrees of freedom. But the part cannot be moved.

Go to Tools -> App Options -> Assembly -> check "Enable redundant relationship analysis." Then go to Manage -> Rebuild All. You will see Insert:7 and Insert:8 are marked as redundant. Suppress or delete them. After that, 0005474118 will be free.

I suspect this has something to do with the assumption the constraint solver makes, in order to solve other assembly constraints. Insert:7 and Insert:8 are not needed. They can be safely deleted.

Thanks again!

Re: I can't preview my Assembly constrains

ethanfL67BY — Fri, 13 Feb 2026 14:11:56 GMT

@johnsonshiue

Hello Johnson,

Thank you for the quick reply! I gave it a try, and it did work! Thank you for helping us out. It took me a while to find the insert mates with the blue i. I ended up having to dig through the model tree and expand all the relationships. I was expecting it to show the design doctor and letting me know what mates were redundant.

That is a similar problem I was having earlier here with blue i. Here’s a post I made in the inventor ideas forum. https://forums.autodesk.com/t5/inventor-ideas/blue-doesn-t-flag-design-doctor/idi-p/14005903

Give it a vote if you think the design doctor should flag the blue i errors.

Again, thank you for your help Johnson!

Ethan Foss