Skeleton Models

[Arbiter]

Hey Folks,
I am working on a project that will require a rather large assembly that could have man different parts changes in the future. I have heard about using skeleton models in assemblies. Does anyone have some good resources to read up on these types of models and how to successfully implement them? Thank you!

-Chris

 

[jsantangelo]

Leo Greene has 2 videos on his site. Check out all his tutorials. They are some of the best on the net.

http://www.e-cognition.net/pages/TDD_Mechanism.html


Also checkout the Worthington Sharpe tutorials. He mentions some on his site. His tutorials are great too.

 

[Arbiter]

Thank you James!

 

[dgs]

If you have access to the PTC knowledge base, do a search for 'skeleton chair' or top down design chair' or something like that. They have an old demo of developing an office chair using skeletons that was how I got started. It's basic, but does a good job of an overview of the concepts. I never do a multi-part design without one anymore.

The basic idea is to place anything that two parts need to share in the skeleton, copy it down into the parts and then use those copied items as references for the part level features.

 

[design-engine]

there are essentially two main family of skeletons and there are muliple variations of each. Most people do the first type described.

One simplifies how an assembly works. Take a piston assembly created from curves for example. The curves dictate how the assembly should function.or maybe with respect to ergonomics one might model a Microsoft mouse with curves and surfaces and use it as a skeleton to segregate each part of the mouse ie. buttons from main and lower housings.

The second type simplifies an already complex assembly and we need to simply a set of surfaces for routing a cable thru the complex assembly. Take for example an airplane fuselage and all the compartments and bulkhead geometry. My task is to route cable and harness geometry thru all the assembly but I only have four gigs of ram and my airplane is far too large to call into memory. In this example i use copy geometry to reach out of my harness skeleton to grab one surface of the bulkhead and/or one surface of the fuselage so I can rout my cable harness down the length of the airplane.

Some will utilize shrink wrap in this described example but for most complex geometries as a satellite or a predator drone I would assume that copy geometry would be used to simplify the already complex assembly. In many cases top down design/skeleton is used to create the fuselage. This technique works in the opposite because I take the existing fuselage to simply create a part that can be used to simplify just to rout the cables.

Edited by: design-engine