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Copy part problem - Multi body

Hi,
I create a part, with copy part feature, and I select an assembly with many part and psm.
Now I have 1 body.
I produce some features.
Now I change the position of a part. 1 border on surface.
When I update the copy part file, it produce 2 bodies.
The problem is that the features goes in errors.

I do another test. I create another part by copy part and select construction bodies. So I obtain a lot of bodies, by activate the bodies as project.
I produce features that erase multiple bodies and it works....BUT...
if I add, in the assembly, another part that also exist in the assembly, when I update the copy part file, It rename all the bodies! and the features are lost.

How can I solve it?

thanks!!!!
7 REPLIES

Betreff: Copy part problem - Multi body

Hi @Cek

 

 

 

I have tested Your first case using a simple example here.

And Yes, I can confirm that after any change in the assembly a new Design Body is added to the associative part with part copy.

And the changed part gets the Dseign Body number of the previuos body so that any features now only belong to the cahnged part/body.

This - her in my example - created cut outs somewhere in empty space since there was no body there anymore. Although the new body - but inactive body - just is on the right place.

 

Solution I found:

 

Go to the Part Copy feature and do a Boolean Union from any new body to the basic primary body.

Afterwards You again only have the one and same base body to which all features belong!

 

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This of course is an extra step tp do but it solves Your problem until development can fix this or explain the idea behind.

 

 

 



regards
Wolfgang

Betreff: Copy part problem - Multi body

[ Edited ]
Thanks @hawcad , it solves, but the problem remain if the union is impossible to do.
If you CHANGE the position of 1 part in the assembly in this way: 1 point corner, or 1 border, on surface, so only 1 point or line of the part is touching 1 surface, the union fail.

Betreff: Copy part problem - Multi body

Hi @Cek

 

 

of course this is an old and wellknown beahviour of Parasolid that it doesn't allow a single body volume with a singularity

 

And this IMHO makes sense too.

Imagine a single piece of material where the volume is sized down to a single point.

What would hapen with such a part?

Yes, it will break exactly there!

So to avoid this situation You either can prevent Your parts in the assembly to have a point/point or point/line connection - ergo the build a singularity in volume, which later on will not allow to have this copied into a single body.

 

Or if You insist on that, then to it first before copy them into a part.

Then You might have several bodies right from the beginning so that every later feature will exactly know to whom it belongs.

 

 

Or, and this is my more interesting question, why do You not use Assembly Featues instead.

This will beware You of making part copies and it also gives YOu the option to have those non-manifold bodies there.

 

Sometimes You have to use the streets, the software and the environment offers to You!

And sometimes they will not allow Oyu to cross these limits.

 

 



regards
Wolfgang

Betreff: Copy part problem - Multi body

we use assembly features from years.
But aren't stable. They breaks often.
We have assembly "child" with 50-60 parts and sheetmetals and we use an assembly "father" with assembly features (70-80 features).
When we change position, geometry, etc. from child, then the assembly features of the father sometimes breaks, without reason. The sketches of the features become Brown....often.
we activate, update, but nothing.
So we are searching a new way for not use assembly features.

Betreff: Copy part problem - Multi body

Hi @Cek

 

 

so then as menitoned:

 

 

Avoid non-manifold situations and theer will be no further problems.

 

 

 

But BTW how to You procede after creating features in the Part Copy?

 

You will changed geometry, but how do You bring that information back into assembly?

 

 

 

 



regards
Wolfgang

Betreff: Copy part problem - Multi body

Hi @Cek

 

 

 

there is one other idea I have:

 

"Put the cart before the horse from behind!"

 

Use the "multibody" functionallity even more!

Create a single part file with Your part/psm bodies in it.

Here You can create Your features as You want, even they are valid for several bodies.

 

And You can export them into an assembly automatically and associative.

 

Think about that!

 

 



regards
Wolfgang

Betreff: Copy part problem - Multi body

Thanks but we can't use multi bodies for the assembly child.
Because we must use different material for parts and sheetmetal, and we use different thikness for sheetmetal.