Derived item loses joint

[mikLamming]

I am clearly not understanding the conceptual model for "Derive".   I have reduced my challenge to the simplest model of which I can conceive that shows the issue.   Could someone please straighten out my brain for me? 😊

I have a test design, shown below,  called Assembly that has two components, a RedBlock and a GreyCylinder.  They are jointed (at a distance) with a fixed joint.

I have a 2nd design called "Target" that has a GreenBlock at the origin.

  

Task: insert the (Red+Silver) Assembly into the Target and make the whole assembly revolve around the GreenBlock. 

Method 1:

Insert/Derive Assembly into Target

So far so good...

Specify joint

Not what I want:  Only the red block moves.  Even though RedBlock and GrayCylinder have a fixed joint relationship, only the red block is repositioned.

Try another way...

Method 2

In Assembly, make a new component "BlockAndCyl" combining the two original components RedBlock and GrayCylinder.

Insert/Derive the revised Assembly into Target.

Define a joint as above.

Not what I want again: Same result.

Method 3

Insert Derive just the new component BlockAndCyl, not the whole Project.

Not what I want:  Same result.

Method 4

Insert derive the compent pair

Not what I want: Same result

What don't I understand about this process please?

//Mik

[kellings]

Hi @mikLamming Derive is meant to be a one way copy with a link back to the original model. Not all things from the original model will propagate to the file that component(s) are derived to, such as joints. You can make changes to the components in the derived file and they won't propagate back to the original file. However, changing the original file will propagate those changes to the components of the file where those components were derived to. 

Instead of deriving an assembly to a new file, is there a reason you don't want to just insert that design into the new file? Joints will absolutely come across in that scenario. Small tip, in the original file, make sure one of the components is jointed to the origin so it can't move. I typically do this by using an as built joint and then selecting the component I don't want to move and then selecting the origin folder in the browser and applying a rigid as-built joint. 

A common thing I see users do is to just ground the component in the original assembly and then they try to use that assembly in a new design. The ground only persists in the original assembly and is not honored in any designs that assembly is used in. 

Does that help?

Thanks,

Kevin

[mikLamming]

Kevin,

Yes, I think that will help a lot. Thank you. Sir! That's spectacularly
clear and concise explanation..

Assuming I understand what you mean by "inserting", my rationale for not
doing so was that I wanted joints, appearance, material and so forth to
propagate - at least until I figured out what I didn't need in the target.

When you distinguish "insert" from "derive" I am wondering if you are
distinguishing the create/derive, which I think of as a push model, from
the insert/derive which seems more like a pull model? Are the properties
propagated in one different from the other.

Your "small tip: grounding" knowhow is pure gold.

My head hurts less 😝
Thanks.

Mik

[kellings]

When you insert a design (component or assembly) into another design file, the design you insert (by right clicking on the file in the data panel and choosing insert into current design) is linked to the original, but also honors the joints that were created in the original. So any changes you make to the original will update in the design where it is used. 

Hopefully that helps. 

[mikLamming · Accepted solution]

Kevin,

The grounding tip was actually the main learning tip for me.  

My other confusion was more a UI issue.  When you drag&drop, or derive a project containing multiple components jointed together,  only the imported component with the newly attached joint moves to the target position in the UI, which makes it look like it will not complete correctly.  But when you "accept" the proposed joint, then the rest of the imported configuration springs into place as required.

Thanks again.  All is now working as I wanted.

Mik