transform an assembly into a part

[Juju]

I have an assembly with 2 parts. Is it possible to merge these 2 parts in order to create a new ''big part'' (instead of the assembly) ?


I would need this ''big part'' in order to add rounds needed for a pro Mechanica analysis.


I tried ''protusion'' in the assembly mode to represent the rounds, but then, the rounds are ignored when the mesh is created with Mechanica.


thank you.

 

[design-engine]

Use copy geometry a proven top down approach. If you
have not used top down design before then I will explain. WF3.0
has a wizzy wig editor. below is the WF2.0 way.



1. Bring up your two parts into memory.



2. Create a third part.



3. While in the third part reach out using 'insert' 'shared data'
and 'copy geometry' and hit open then default and grab the first part.



There is a trick to grab the first part.



4. Left click on the solid geometry and right hold down to select
'Solid Surfaces'. Then Choose OK and OK Or middle click
twice like a pro so no one in your office can see and they think your
fast. (bet 30 cents wf update classes don't show you that)



This way you can make modifications to each of the two original parts
and not fail the copy geom feature. Works real nice and
there are many off shoots to this style of modeling that one might
cover in an advanced 'assembly class' at PTC training. I never
took that class or any PTC class but I suspect that is what they cover.



5. Now do the same to the other part (follow steps three and four again)



6. Now you should be sitting in the third part with two separate
surface quilts. Simply merge the two surfaces. It is tricky
if you do not know surfacing because of how to select the surface
quilts.



7. Now solidify the new merged surfaces by going to 'Edit' 'Solidify'.



Now you got two of em and you have one part from two. The
new part is associative in that if you modify the original parts the
new part will update and not fail. The only way you can get the
new part to fail is if accuracy becomes an issue or if one part moves
far left and the other part moves far right. Then the merge may fail in
the new part.









History of top down design...

Top Down is a strategy for information processing.
Each part of the system is then refined by designing it in more detail. I
believe 'Top Down' comes from Software programming and was first used before
1980. in our finite intelligence we can only focus on one
thing at a time which is why I like top down design. (that is why most
engineers get divorced because they can only focus on one thing at a
time... Hence the absent minded professor always loosing his
keys. And why you probably almost always walk out to your car
without one thing or another.) Top down design lets us think about the big
picture and small details later. To have good design, understanding of
the complete system is usually considered necessary. The alternative of
Top Down design is bottom-up or in engineering we call Piece Part modeling. For
example. Bottom-up is to focus on the individual part out of context to
the whole. Then as a second in piece part design one has to step back later to look at the way the piece interacts to
the assembly. "This part interferes with another so I have to
modify one part so it does not interfere." That is the piece part approach.
The top down approach will not have interferences because of your process.







As related to Pro/E....

I can almost recall hearing PTC use the phrase 'top down
design' I should ask to verify but I don't think it was
before 1997. In 1993 we used a technique in assembly mode
to merge from other parts. One example I remember was 1994 while
working at a design firm in Chicago. Client was Duracraft based
in China. The fan housings required different shrouds and when
you work at an industrial design firm, you are always under pressure to
go fast. So in an hour I used a merge function to basically glue a
shroud from on fan to another fan. Merge gave me one fan shroud on anather motor cover back fast.

Next came what I called 'motif options' because users at the time
were using this
merge function to sweep the face of a product for other markets.
A pager for example can be sold into different markets with the same
b-side geometry and have different looks on the outside. With
motif options and merge tools let product engineers accommodate
industrial
designers to make all the motif changes they want and not have to
rethink the base geometry or b-side geometry. All the
original data and any changed to the b-side geometry was done to a
master part. There comes the next word master merge. I
think that takes us to about 1997 or so. Curves became a problem
because they took more time to manage properly.

This technique was later called master merge but had a different
technique that was more robust and sound... Most users used
an assembly but it was not required. ... Then came skeletons in late 1997.



Version 20 rolled around in 1998 and that was where skeleton modeling
first appeard as an organized feature in Pro/E.


Advantages of top-down design:

a. Stay focused on the end goal

b. each team member knows their specific job function and all parts reference the skeleton

c. When design in Pro/E commences there are no fundamental questions

d. Design has distinct purpose and there is little confusion

e. less mistakes

f. looks good on your resume

g. get the job done fast *see same for disadvantage



Disadvantages:

a. Top-down may complicate things

b. Cant test (FEA or Structure) individual piece parts until design is complete.

c. All design decisions are determined at the start of the
project and the overall goal of the project is determined and
this may limit outcome.

d. get the job done to fast (if you bill by the hour) *see same for advantages

e. too much of the details of a design are linked to the skeleton and effects regeneration times.



I thought this history stuff might be interesting for the group.





Edited by: design-engine

 

[dougr]

"Top Down Design" simply refers to the fact that certain components can only be designed in an assembly.


Examples:

1. 
   <LI>Weld runs between different components.
   <LI>Wire/cable runs between components.
   <LI>Ship hull frames etc.
   <LI>Aircraft frames, stringers, bulkheadsetc.
   <LI>Any component whose shape relies on the positioning and shape of1 or more components with irregular mating surfaces.</LI>

The prob with defining features and parts in assembly mode is that the assembly requires information to be written to each part - this information is typically termed "external references" - affected.


To manage external references you must have (1) ownership of all the parts referenced and (2) very careful and precise file/file structure management.


External refs are not for rookies and should only be managed bythe most experienced users.


Bottom-up design is almost always preferable as external refs are avoided.


PS When you think about it "Top Down Design" has been around since Captain Caveman, it can be amusing/bewildering watchingthebrain boxesin these software companies think they have stumbled into something new...
Edited by: dougr