Can't move unconstrained parts within an assembly

[ben_walker5]

Hi, I have been building an assembly and suddenly I am unable to move parts according to their constraints. I can move them as soon as they are placed but as soon as I add one constraint it's as if they are glued in place. For example, when I line up two holes I can no longer rotate one part around the grounded component.

Have a turned off some functionality of the program?

Any help would be much appreciated!

Ben

[JDMather]

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@rjezuit wrote:

Do you use the demote function to build your subs? ....

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I specifically indicate in previous post  (sub) - assemblies pushed out from multi-body solids master Manage>Make Components.  All the parts are grounded by default.  Any changes are controlled by the master.  The sub is constrained in the main assembly.  Demote is not part of this.  (and yes, I do use Demote when appropriate, but that is a completely different topic than the topic I was trying to illustrate).

[douthett]

To JDMather 

I'm curious how big are your models that you are grounding everything? 

[JDMather]

Not big.

And I rarely ground everthing - only in certain cases (as already described, multi-body and Frame Generator) and these are generally subs that are constrained in a main assembly.  Anything else that I absolutely know is never going to change and has no kinematic interest.

[Breeze104]

I was told by Autodesk rep....NEVER GROUND your parts...contrain base part via plains and lock it down that way.

[JDMather]

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@Anonymous wrote:

I was told by Autodesk rep....NEVER GROUND your parts...contrain base part via plains and lock it down that way.

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Does this "Autodesk rep" have a name?  Contact information?

I suspect there was a bit of information lost in translation, perhaps a design specific recomendation.

[Breeze104]

I was just begining using Inventor and my models were simple, I think is was around ver 5 when I was first told this.

I don't remember the first Tech to tell me that, but If memory serves me correctly.... The last Tech to tell me that was a tech from Avatech Solutions (ImaginIt...now) and he moved to greener pastures with another company.  I hadn't been grounding any thing for several yrs and he said that it was better to "not ground" parts in assemblies, so I have just stuck with it.

[blair]

I usually don't have more than the base part grounded but there would be a slight increase in performance with all parts grounded over just the base part grounded. There is just that much less information (constraints) that needs to be loaded and read by Inventor to properly position the parts in the assembly.

If you make a copy of a IAM and ground all parts and delete all the constraints you will find the file size slightly smaller and the model will load slightly quicker.

[kb8fu]

I just ran into the same issue with Inventor 2014. The little red cross showed an inconsistent constraint on completely different subassemblies used in the offending assembly. I deleted that inconsistent constraint and can again drag unconstrained parts around. This also solved a problem with relocating holes and the parts constrained to them not moving to their new locations.

[Curtis_Waguespack]

Hi everyone,

 I might have missed it if someone has already mentioned this app, but if not have a look at this app, as it seems to give the best of both worlds concerning the ground all, vs never ground all question:

https://apps.autodesk.com/INVNTOR/en/Detail/Index?id=appstore.exchange.autodesk.com%3aassemblyfix_wi...

I hope this helps.
Best of luck to you in all of your Inventor pursuits,
Curtis
http://inventortrenches.blogspot.com

[k.anderson328]

This usually happens when I have an Adaptive scketch on a part. One way to solve this problem is to delete all projections in the sketch after you have traced over them.

Right click the sketch in the tree, then delete all projections, then Rigth click the feature and uncheck Adaptive.

This will keep any kind of extrusion, Cut, or Feature on the part your working with but delete it's dependancy on another part or assembly.

[Rusty_Shackleford]

Kind of off-topic from the original post, but since I've taken a liking to the multi-body assembly process, I'm kind of curious how you get your component positions to update in the assembly once they're grounded? I get the part definitions to update, but if I just change their position in the master file, the position doesn't seem to update (probably because it's already grounded). Do you just delete the component from the assembly and go through the whole make component process again, overwriting the old part? Or is there some nicer method that I don't know about?

[JDMather]

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@Rusty_Shackleford wrote:

Kind of off-topic from the original post,...

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Start a new topic (this thread is very old), and attach your assembly here that exhibits this behavior.

Because the components are modeled in body postion, changes should update.

[r_blackburn3000]

I had a similiar issue, as I backtracked & started deleting parts from the bottom up on my browser I found that arraying a component in an assembly had something to do with it.Works fine now, I had no conflicting relationships, no adaptivity, & did a rebuild all, and it still didnt flag me.  running inventor 15

[hjrios.c]

So I think I was having this same problem hopefully this will help somebody, for posterity sake

[Kurtis1]

I've had a similar problem. It's not necessarily a problem with your mates so before you "blow up" your assembly by deleting all the mates, try closing inventor and re-opening the file. For some odd reason, Inventor decides to forget about it's ability to click and drag things whether you work in assembly or working with layouts. 

[johnsonshiue]

Hi! In general, when there are failed constraints in the assembly, the constraint solver will try to resolve it every time the constraint is computed. This behavior helps find the best solutions in given constraints. However, it can introduce strange behaviors from time to time. The rule of thumb is to keep constraints healthy as much as possible. When there is a failed constraint, either fix it up or delete it. Otherwise, you will end up with more failures and you don't understand how the constraint system works.

If you see an unreasonable behavior, please provide an example. We are happy to take a look and see if there is room for improvement.

Many thanks!

[barbtobey12]

Inventor 2018 - removed "ground" on all of the grounded components - worked!

[allan.dolby]

So I have dealt with this problems a fair few times whilst using Inventor, I find the solution that always works for me is to delete any angled constraints.

Hope this helps any future sufferers!

[johnsonshiue]

Hi Andy,

If there is no pre-existing failed constraint and the part is not adaptive, the behavior is not right. There is no need to delete a solved constraint in order to free up a under-constrained component. If you see it again, please share the files with me directly (johnson.shiue@autodesk.com). We need to understand the behavior and see what we can do about it.

Many thanks!

[anthony.eib]

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@Barvas11 wrote:

I have the same problem. And as rjezuit says, try to ungound your parts. Every assembly should have only one part grounded no more than that. Another thing that could be causing this are adaptive sketches and parts. You should always turn the adaptivity off. 

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Thank you. Turning off adaptive sketches solved my problem.