Assembly Features - How exactly do they work??? (do they?)

R2017x

I'm trying to create an assembly hole.  I want it to be effective ONLY at assembly level, and ONLY against one instance of a particular object.  So far, every attempt to do this eludes me.

What I've done:

1) Created assembly hole

2) Set the affected representation (is it possible to set an instance?)

3) Updated the "Solid Impact" feature in the part

4) Wallowed in my disappointment, as the feature appears in all instances

This is really not a well documented feature, and is not working as expected. I don't even seem to have control over how to constrain the location.

Hello,

There are no real assembly features in CATIA. To bypass this limitation you have to create a Derived Representation in your assembly.

I don't believe this is true.  I have seen the assembly features in both the documentation, and presented by Dassault.  Recently, I asked our rep, and he showed me a working example in 2020x.  I was not able to get it to work, as shown, in 2017x.

I'm not sure what your angle is with the derived representation.  I don't think it's correct, at all, but maybe I'm misunderstanding what you're saying.  Please provide more details.

Matt,

I'm very curious to see what your DS rep showed you !! The CATIA assembly features from the Assembly Design App are impacting the reference parts and this is not what customers usually expect. It's in fact a productive tool to create in one shot a feature (hole, pocket, removal,etc) inside several parts of the same assembly.

I attach a video showing the "Derived Representation" methodology. This process is already in use by several customers (V5 and 3DEXP.)

Regards,

Serge

Thanks for the example.  Unfortunately, I had a feeling that this is what you were going to show me.

Of course, the point of the assembly features, should be to not generate new part numbers.  How do you get around a new part number in Enovia for this example?

The example that I was shown, depicted the same part number used in 2 locations, but with an assembly operation affecting only one of the parts at the assembly (weldment) level - thus preserving the part number at the detail level.  For the purpose of doing anything else - and especially when part number cannot be retained - I can't see why we wouldn't just create the part as a unique detail, perhaps even just publish geometry down to the detail part.  For most parts, the derived representation seems like extra (non-valued added) steps.  (Derived Rep vs Duplicate)

I suppose there are probably use cases that I'm not considering.  But for my purposes, this is generally going to be structural parts.  Tubes, angles, channels, etc.

It's impossible to affect only one instance due to the CATIA reference/instance mechanism. if you modify one instance, all the other one will be also impacted and identical. Believe me this is a behavior well known since the beginning of CATIA V5 but unfortunately there is still no development plan to improve it.

Yes, understood.  Which is why I was surprised to see the "Assembly Features" show up in 3DX.  

However, I was shown a method to achieve the result.  It was presented to our users, and I have a copy of the demo.  I will need to go back over it, and pay attention to the details.

If the assembly feature doesn't have some sort of overriding effect on the detail part, then it  would seem to be a completely vestigial function.