Constraining Removable Parts (Conditional Constraints?)

[Anonymous]

I have designed and assembled a check fixture in Inventor, and I have constrained it to the part being checked using limits. This method works great for demonstrating how the part is checked using the fixture, however I would like to be able to move the part freely once completely removed.  Is there a way to constrain the part and the fixture such that limit constraints are only active when the part is in the fixture?

I have included a screenshot of a basic example of what I am trying to do.

The round tube is constrained to the block by the three faces that it may contact. I used tangent constraints with a lower limit of 0 and no upper limit. I would like the tube to be able to move freely after being removed from the block.

[CCarreiras · Accepted solution]

Hi!

Simple way.

Create both constrains, that one that fix the system and the other one you can have limits to have a dinamic system.

Go to Constraints folder and rename each one as STOP (for the fixed fixture) and the other as MOVE (constraint that permits movement). (Note: Rename is just to find and identify better the constraints in the folder).

When you want to have movement, Suppress the STOP constraint and UnSuppress the MOVE Constraint.

When you want to fix the system, SUppress The MOVE COnstrain and UnSuppress the STOP Constrain

[swalton]

To expand on what @CCarreiras recommends:

I use a series of different position reps to manage my constraint sets.  In this case, I might hold the test part in place with limit constraints in the Master Position Rep.  Then I would make a new rep, called "Flexible" and suppress constraints as required. I would use the "Flexible" rep when I want to drag components with my mouse.  If I needed additional fixed positions for various components, I'd make new reps for each one.

The position reps sort and organize the various constraints for me.  I don't have to dig through several hundred constraints in my Relationships folder to change suppression states or offset values.

[Cadmanto]

Sounds like what you are going to want to do are what called position representations.

https://forums.autodesk.com/t5/inventor-forum/how-to-reflect-flexible-sub-assembly-position-in-view/...

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[CCarreiras]

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@swalton wrote:

To expand on what @CCarreiras recommends:

I use a series of different position reps to manage my constraint sets. 

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And here we have the.... not so simple way!!!... 

[Anonymous]

@CCarreiras @Cadmanto @swalton

Thank you all for your responses! I may have been asking the wrong question though... If I constrain only the critical elements, but allowing the free movement that I desire, is there a way to detect any intersection/interference of part and the fixture? In other words, can I apply a few critical characteristic constraints and have Inventor generate a report on if the part passes or fails? 

[CCarreiras · Accepted solution]

Yes, you can:

You have to create a Contact set between the parts you want to study (or all the parts in the assembly, depends on the power of your pc).

Just select the parts, right mouse button and select "Contact Set"

Next, activate the contact set in Inspect tab.

If you drag the part manually, parts will behave like the physical world, and when they collide, they will stop.

Tip: you can use drive constraint to make the part move along the path and it will stop when colliding.

To check interferences, again in Inspect Tab, try the Analyse interference. In this case, this will be a static analysis.

Now.... depends on what you want to achieve.

[Anonymous]

@CCarreiras

That is EXACTLY the answer I was looking for. Thank you!!