topic Re: Complicated Assembly Problem in Inventor Forum

Complicated Assembly Problem

Anonymous — Mon, 01 Feb 2021 15:53:17 GMT

Dear sir,

The attachment is a big assembly file , 443 parts, I is the work of more than a year and I have problems with it as below.

In the below picture and as you see

1- the bolt (in the black circle) is seen fly where I have tried to delete it normally but I couldn't then I deleted its constraints and the allied parts but the result , I have entered a mess. Is there any help please? Also, some parts and subassemblies are behaving abnormally and disappear by itself and I don't know how and why.

2- In the Green small circle in the Tree, this symbol appears by itself and I do not know why it appears, is there any reason and how to avoid it?

3- As you see in the Red circle, I don't know how did these symbols appeared and why? Is there any explanation?

Also,

Re: Complicated Assembly Problem

bwatson1967 — Mon, 01 Feb 2021 16:30:17 GMT

In the red circle if you right and scroll down to the tree you will see you probably have flexible enabled for positioning, if you uncheck your results you are looking for may appear. Undo right away if this does not fix the issue.

Re: Complicated Assembly Problem

swalton — Mon, 01 Feb 2021 16:48:57 GMT

Questions 1 and 3: Incorrect Constraint solves and The Flexibility icon: These sub-assemblies are set to Flexible. This means that the sub-assemblies' component location is driven by constraints in Main.iam. Flexibility is powerful, but can lead to unexpected results from Inventor's constraint solver. I use it when there is no other way to show the correct motion of the parent assembly and I judge that the potential problems are worth the effort of fixing them repeatedly during the design process.

One potential problem is that Inventor's assembly constraint solver will fail to solve, but not trigger Design Doctor (red cross icon). I usually notice this issue when other constraints, like the ones for the bolt, fail to move correctly after an assembly update command. Check to make sure that each flexible sub-assembly solves correctly when open by themselves. Once that is working correctly, check to see that they solve correctly in Main.iam. That should help you find any other sick constraints in your upper level assembly.

Question 2: The green marker. The lightning bolt icon indicates that a component needs an update.

It looks like the 235- Upper Back... part is used twice in your assembly. One instance is set as adaptive and changes as the Main.iam assembly constraints require. The other instance is placed as a normal part. Both instances have the lightning bolt icon. The icon will go away after you update Main.iam. You may need to correct any Main.iam constraint issues releated to the Flexible sub-assemblies before Inventor will stop making changes to the adaptive instance of 235- Upper Back...

Re: Complicated Assembly Problem

Anonymous — Tue, 02 Feb 2021 13:57:46 GMT

Thank you for your reply

As you see in the below picture there is no Flexible

Thank you

atajabbas

inventor 2020

Re: Complicated Assembly Problem

swalton — Tue, 02 Feb 2021 15:00:06 GMT

Ok. The assembly icon shows it as flexible. Have you checked how the assemblies behave when all are set to the MASTER Level-Of-Detail? Your main.iam shows that it is in Level-Of-Detail:6, which is a default name. Did you intend to create a LOD as part of a memory management exercise?

I also see that you have left the main.iam in Express Mode. I only use Express Mode if I am reviewing a completed, ready for production, design. I find that I miss commands and functions that Express Mode hides when I am actively modeling. I'm not sure if the flexible command is one of the hidden ones.

Express Mode is useful if your PC does not have enough power to run a large model. 2k instances should not be a problem on a reasonable workstation computer.

Try changing the LOD to Master, and/or exiting out of Express Mode.

Re: Complicated Assembly Problem

Anonymous — Tue, 02 Feb 2021 15:20:42 GMT

Many thanks for your kind reply.

But, how to correct those constraint issues? I afraid that I may spoil the work if I do it by my self, because normally there is a triangular yellow icon before the damaged constraint and I do not find that. Would you please help me to find or indicate the wrong or noncorrect constraint.

thank you,

atajabbas

Inventor 2020

Re: Complicated Assembly Problem

cadman777 — Tue, 02 Feb 2021 22:06:52 GMT

If that was my assembly, I would do like SWalton says:

1. Get rid of the Flexiblility in all the sub-assemblies.

2. Try to update the top-level assembly and see if the Lightening Bolt disappears.

3. If not, then I would seriously consider getting rid of the ADAPTIVITY and getting those references into those parts another way. I NEVER use Adaptivity, b/c it ALWAYS bits me in the end (so to speak). The bigger my top-level assembly, the WORSE it bites me! And the more work it creates down-line.

4. The parts that 'disappeared' may be way off in 'outer space', so if you select them in the browser and click on ZoomSelected, you may find them WAY FAR AWAY from your assembly, which means you have a Constraints Conflict that needs resolving.

5. If you have Constraints conflicts, then if you turned off Adaptivity, the related parts may be causing it b/c the constraints may be on parts that don't connect due to Adaptivity not allowing the part features to relocate, b/c Adaptivity breaks a LOT, which means the features in those parts may be out of proper position relative to the assembly.

5. In that case, what I would do is find the Constraints that are broken, and suppress them to see which ones will make my assembly go back to normal. You may have to fiddle around with Suppressing and Unsuppressing Constraints to find the offending constraints, b/c many times the healthy Constraints are YellowTriangled and not the broken ones. So it could be a trial-and-error operation.

7. After finding the offending Constraints or part features, then I would work on fixing the CAUSE of the problem at the Part level, which in the case of Adaptivity, may mean a LOT of re-work, or it may mean you can 'cheat' by adding a few work features to the parts in question or 'fake' the dimension by manually measuring it in the top-level assembly and then manually copying that number into the feature of the part in question (all depends on how you modeled your assembly and parts).

That's usually how I resolve such complexities.

Like process of elimination in automotive diagnostics, you narrow it down.

FIND WHAT IT ISN'T, THEN YOU KNOW WHAT IT IS.

Re: Complicated Assembly Problem

swalton — Wed, 03 Feb 2021 16:27:41 GMT

You might try the Rebuild All command on the Manage Tab of your Main.iam file. It may help Inventor display any bad constraints.

Turning off Express Mode, working in the Master LOD, and eliminating any flexible components or adaptive parts are steps I would take as I tried to troubleshoot a model I built. I might also put all my assemblies in the Master Position Representation. That way I give Inventor the simplest constraint set to solve.

If that failed to show why the bolt is not moving correctly, I'd suppress all the constraints on the bolt, check that the assembly solved as expected, then un-suppressed each bolt constraint and recheck. If any of the bolt constraints causes the assembly to fail to solve as expected, I would work through how I am constraining the bolt and see if a different combination of constraints works better.

However, the bolt may just be a symptom of a different assembly constraint causing the problem.

It is almost impossible to troubleshoot these types of issues without the actual design files. You might consider making a pack-n-go of the main.iam and posting a link in this thread. Other users might have some time to look at the file and see if they can find a fix. Remember that this is a public forum, so don't post anything you need to keep confidential.

Re: Complicated Assembly Problem

Anonymous — Wed, 03 Feb 2021 18:57:43 GMT

Hi Mr. Swalton,

Many thanks for your kind replies.

Once I have turned off the Express mode and every thing returns OK, where the the flexible mod worked and has been turned off and as it are the bolts. Indeed , I didn't know how the Express Mod jumped in the commands ribbon and I don't know where can I find it and what is the function of it? Could you please, tell me?

Every thing now becomes normal and I work now comfortably up to this instance.

Many thanks for all other friends who replied me and gave me the help

Again Mr. Swalton, many thanks for your kind help.

atajabbas

Inventor2020

Re: Complicated Assembly Problem

Anonymous — Wed, 03 Feb 2021 19:14:51 GMT

Hello,

Would you please tell me what is the LOD and what does it mean? and what is the Express Mode and where I can find it? What is its function?

Thank you

atajabbas

Inventor 2020

Re: Complicated Assembly Problem

swalton — Thu, 04 Feb 2021 14:49:14 GMT

Here are a few links to the online help:

Express Mode

https://help.autodesk.com/view/INVNTOR/2020/ENU/?guid=GUID-34C9AE4C-EDA7-4E46-AD51-3383A67FF1B9

LOD, a common abbreviation for Level Of Detail Representation

https://help.autodesk.com/view/INVNTOR/2020/ENU/?guid=GUID-BB22DDCB-F370-4BF0-B438-EC1D0E91D49E

Re: Complicated Assembly Problem

Anonymous — Thu, 04 Feb 2021 20:31:13 GMT

Hello sir,

As I was happy that the work becomes well. suddenly appeared bulbs beside some healthy constraints and Yellow Triangles beside other that was healthy constraints and the work entered in mess. I have become terrified and frustrated because some adaptive parts behaved abnormally Then I closed without accepting any changes and before taking any screen shots because of the frustration.

The question is "" if I remove adaptive state , is there any effects on the work even after or during progress ""

I'm frustrated and terrified because the work of more than a year may be damaged or failed.

Thank you

atajabbas

Re: Complicated Assembly Problem

Anonymous — Fri, 05 Feb 2021 16:34:04 GMT

Hello sir,

As it is seen in the below picture , please note the red circle in the browser. it is around

I removed the Adaptivity of a part , but a blue circular icon with an i inside it has appeared beside the part instead of the Adaptive symbol. Would you please tell me if it is dangerous or may bite during progress in the work?

Thank you

atajabbas

Re: Complicated Assembly Problem

Anonymous — Fri, 05 Feb 2021 17:30:44 GMT

Hello sir,

As it is seen in the below picture , please note the red circle in the browser. it is around

Thank you

atajabbas

Re: Complicated Assembly Problem

cadman777 — Fri, 05 Feb 2021 23:11:59 GMT

I believe it's telling you that part is now DISCONNECTED from the parent (the part that you got the derived geometry from). So make sure you KEEP A LIST of all the parts and Parent/Child relationships when delete Adaptivity, so you can go back later on and fix it if you need to. I never use adaptivity b/c of the many problems it causes. It's 'best practice' to not use Adaptivity. Use global Parameters or derived Parameters instead. But make sure when you do that you don't get Circular Dependencies.

Re: Complicated Assembly Problem

Anonymous — Sat, 06 Feb 2021 12:55:29 GMT

Hello,

Thank you sir for your kind reply.

It seems that I have to rebuilt the project again from the beginning and avoid any Adaptivity and other wrong issues, It will be faster than look for or investigating the errors, It will take some months , and this is a better way to overcome and avoiding the problems .

Many thanks for all who helped me in correcting my errors and who directed me to correct my steps

Thank you

atajabbas

Inventor 2020

Re: Complicated Assembly Problem

cadman777 — Sun, 07 Feb 2021 00:46:02 GMT

Glad you figured it out.

Sorry to hear you had to suffer during the 'learning curve' associated with Inventor's defects.

Hopefully these lessons will set you up for many years of happy Inventor modeling!

Re: Complicated Assembly Problem

Anonymous — Tue, 09 Feb 2021 10:32:18 GMT

Thank you so much