Pro/E skeletons - standardization of skeleton creation and use

[ptc-497811]

Does anyone have any documents detailing their skeleton processes (i.e. creation and use of skeletons) that they would be willing to share?

We are attempting to standardize our process and would like to see how others are creating and using skeletons.

Thanks in advance.

Dan Roby
Senior Designer
AAR Mobility Systems

droby@aarcorp.com

[DeanLong]

Hey Dan,

While I am sure you will get more than enough responses on how to do Skeletons...I suggest you ask yourself...do you need skeletons. WhileSkeletons have there place,I have seen themused any times needlessly and all it ends up doing is creating another level of complexity and managementto the data. Be clear that the benfefit outweighs the downside.

My .02

[DeanLong]

Fixed my typo.....

In Reply to Dean Long:

Hey Dan,

While I am sure you will get more than enough responses on how to do Skeletons...I suggest you ask yourself...do you need skeletons. WhileSkeletons have there place,I have seen themused many times needlessly and all it ends up doing is creating another level of complexity and managementto the data. Be clear that the benfefit outweighs the downside.

My .02

[DeanLong]

Fixing another.....Thanks Lyle....

their...

More coffee please!

In Reply to Dean Long:

Fixed my typo.....

In Reply to Dean Long:

Hey Dan,

While I am sure you will get more than enough responses on how to do Skeletons...I suggest you ask yourself...do you need skeletons. WhileSkeletons have there place,I have seen themused many times needlessly and all it ends up doing is creating another level of complexity and managementto the data. Be clear that the benfefit outweighs the downside.

My .02

[dguidry]

Dean,



Coming from the very large assembly world, I must say that I disagree
with this comment. With all of the negatives that come from assembly
features when groups of up to 40 are using the same model, I prefer to
see a skeleton in just about every assembly (at least those that are
part of our project assemblies). The level of complexity it adds is
minimal and the advantages of users not littering their assemblies with
features is fantastic. We try to "demystify" the skeleton and our only
suggested rule-of-thumb is that users should avoid all assembly features
possible when a skeleton is present. We ask the question "do you need
to NOT have a skeleton part?"



That being said, we do have a methodology on top-down design that is a
little more complex than can be put in an email response. It does use
skeleton parts, but it does not preclude the use of skeletons for other
purposes.



For those not in the very large assembly world, this philosophy may not
apply as the advantages of not littering assemblies with datum features
is of less consequence.



Regards,



Darren Guidry

Supervisor - MCAD Systems and Design Support

General Atomics Aeronautical Systems, Inc.

[dgschaefer]

In my experience, the times when I'm building even a small assy and I
convince myself that I don't need a skeleton are the times I'm kicking
myself later for not having one. Late design cycle changes are sooooooo
much easier when there's a skeleton in place controlling all shared
geometry.

Doug Schaefer

[DeanLong]

Yep...like I said..they have their place. I am not in disagreement with you at all.

That's really all I stated in regard to the original post. Skeletons are a useful method in some regards...not so much in others. Each scenario needs judgement on it's own merits and ROI.

[lwh]

Skeletons definitely have their benefits. Consider an assembly where one of the main (and early) components may (and that usually means 'will definitely') be replaced by a newer version, when all later components reference it, not only for placement, but also for geometry.

Another problem with 'simple' assembly dependencies is the derivation of similar products, which are often generated by just copying the existing assy - this will always keep references to the original, even if it is otherwise obsolete.

So, when starting, not only use one (or even more than one) skeleton, but also make yourself familiar with published and shared geometry, as this will allow You to use reference geometry from the skeleton without creating assembly dependencies. And if You do, then never ever reference component geometry to that of another component. (Use strict reference control, and ignore users complaining about it)

However, don't misuse skeleton curves and relations to simulate complex assembly motions, this will soon end in something hardly maintainable...

[ptc-46674]

Dan

I am very interested in this subject and I have 2 additional questions for the folks out there that use Top down design, skeletons, layouts etc. 1) Can someone go out on a limb and quantify the Time savings, and other benefits of using Top down design. & 2) how many advanced assembly licenses do you need? we have about 15 every day ProE users and I want to say we would only need 5 or 6 Advanced assy licenses.

I have been preaching about the benefits of using top down design to management on and off for about 2 or 3 years now. The problem I have is convincing management to adopt this design philosophy, and do a project using top down design. Currently we only have one seat of advanced assembly out of our 20 ProE licenses. None of our projects are currently done using skeleton models!

Dave McClinton

MCAD Systems Admin / Mechanical Designer

McKesson Automation

[suganthan.mech]

Hello dave

You can use layouts and skeleton for top down design.

If your top down is used by "N" number of users, then you can go with skeletons.
Layout's also good. But need some extra time.

Skeleton is very simple.


1. Draw the sketch(curve) in skeleton

2. Publish the geometry in skeleton

3. Copy that geometry in required parts

4. Then create features in that parts.

From my experience, skeleton is the best method......


Suganthan Rajamanickam
Pro-e System Analyst

[ptc-497811]

Thanks for all the replies.

I think I may have been a little too vague in my first post so I’ll try to provide more information this time around.

We have been using skeletons for approximately four years. As time has passed, our use and development has grown to the point that each design team has their preferred why of creating and using skeletons. We are attempting to standardize our use and creation of skeletons across the design teams in an attempt to be more flexible in personnel assignments (i.e. cross training).

We started using skeletons for many reasons including attempting to eliminate the issues cause by spaghetti constraints (i.e. difficulty opening large assemblies, and long regen times), prevent failures, ease of design changes, defining keep-out areas, as well as collaborative design. Another important note is that we do not use the Top Down Design method (yet) because of our requirements to provide drawings for our production process.

Currently our preferred methods range from a minimalist point of view (i.e. very few skeletons) where skeletons represent approx. 0.6% of the model, to the point of view which encourages nested skeletons (i.e. assemblies of skeletons that have multiple levels) where skeletons represent approx. 5% of the model.

My questions are: (1) Has anyone had a similar issue? (2) If so, how did you resolve it? (3) Did you document your process? (4) Are you willing to share your process or the concept of the process?

Thanks again.

Dan