Re-deriving sketch?

I'm not quite sure how to put this question: I created an assembly X with
parts A and B. Let's call A the "master part" which has no external
references. Part B is based on a derived sketch from A.

By and by the assembly grew bigger and eventually became a sub-assembly of
an even larger one (Y). More parts (C, D) were derived in-context from A
and B. Later it turned out, from a logical standpoint, that A and B didn't
really belong into X but into Y (which also contained X). So I moved them
there with the result that pretty much everything went out of context (B
with respect to A as well as parts C and D). Below are three crude
graphical representations of what the assembly tree looked like at each
stage:

1)
X
+- A
'- B->

2)
Y
'- X
+- A
+- B->
+- C
'- D

3)
Y
+- A
+- B->?
'- X
+- C->?
+- D->?

It seems that due to the reorganization of the project SW lost track of
the in-context or derived-sketch relationships that existed. It did warn
me that this would happen but I didn't have an alternative. This would be
very easy to fix if I could just re-derive sketches from A into parts B
thru D. Unfortunately this doesn't seem to be possible, and since the
derived sketches form the basic feature of all these parts and not just an
"add-on" feature, I can't just replace the feature with a new one.

Is there a good way to resolve this?

--Daniel

 

Daniel,

If you really used in-context references rather than the Derived Sketch
function, you may be able to reattach the references by clicking a line,
click and drag the red dot to an appropriate entity. As Dale says,
though, you're hosed if you used Derived Sketches.

A way around this would be to leave a copy of the part in the original
assembly, but hide it. You can't convert a regular part to an envelope,
which would be ideal. Leaving it hidden isn't ideal, but it keeps your
references from exploding.

Anyway, good luck,

Matt

 

OK, I'm hosed then.

Good tip.

What it boils down to is that it pays off to spend an extra hour on really
thinking how all the interdependencies in a large project are.

My project uses two basic contours (the inner and outer part of sort of a
bayonet mount) that re-appear in various parts that don't have a hell of a
lot to do with each other but are all part of the same assembly tree. Not
so much because they really are going to be assembled in that manner, but
to see how it all moves together.

If I'd start over I'd probably draw a couple of reference sketches at
assembly level and derive the part sketches from those. Is this a good
approach in general, or how would you guys do it?

Thanks,
--Daniel

 

One of the issues with Top Down design is that Yesterday's top is
today's middle or bottom.

 

Sounds a good method, provided the alternate view required is only of a
single part.

Dale, why do you not wish to just add another instance of the part and mate
it at an alternative position, or use another config to show it in more than
one place?

John Harland

 

Hi guys,

thanks for all the help. This is a terrific newsgroup. I ended up solving
my problems by creating a couple of reference sketches at the top assembly
level and by deriving the relevant model sketches from those. For that of
course I had to delete a lot of former model-level sketches and their
associated features -- often followed by having to delete each and every
feature of the model, ending up with a stack of unresolved sketchses.
Sometimes I just hosed the entiere model and rebuilt it from scratch. This
sounds worse than it was; in the end the reorganization of the project
maybe cost me a couple of hours but will save many headaches in the long
run.

Thanks again,

--Daniel

(During this process a new question popped up; I'll start a new thread for
that).

 

A quick followup:

The new top-level assembly sketches are completely stand-alone and depend
on nothing else. Why is it that they appear at the very bottom of the
assembly tree (below mates) and cannot be moved to the top?

Thanks,

--Daniel

 

Am 13.03.2006, 13:14 Uhr, schrieb Seth Renigar

No, it didn't pose any problemsm, I was just curious. But then, as Dale
says,
I just tried again and they just popped right up under the system features.
Go figure.

--Daniel