Top down or Skeleton

[J-C]

Got a new project to create a parametric assembly. 200 or so parts with some sub-assemblies. Question is, top-down.....or the skeleton approach. Any suggestions? I've done some top down in the past but have only played a little with the skeleton approach.

Jason

SolidWorks 2007 SP3.1 on WinXP SP2

 

[josephv]

Hello Jason,

I like top down, but keep in mind it works best for "one of a kind parts in a one of a kind assembly".

If this is not the case you can still use top down, but disable external references.

You can also use equations and have some variables control the critical dimensions.

Yes you can do the skeleton sketch approach, I find it good for weldments.

And finally if your assembly is "configurable" you can use DriveWorksXpress.

cheers,

 

[ctopher]

IMO, if you are using subassy's, better to do bottom up.

Chris
SolidWorks 07 3.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)

 

[MadMango]

I've been working with modular products for the past several years. What I find best is to have a controlling Sketch (skeleton) that the sub-assemblies are constrained to in a Bottom-up approach.

One particular product line has ~50 configurations, ~15 sub-assemblies and ~700 total parts.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[rockguy]

I do a lot of my work top down. First thing I do is create layout sketches in my assembly and then build my geometry referencing the layout sketches as much as possible. I try to keep any reference to other geometry in my assembly to a minimum. I also base my mating on the layout sketches and planes.

I do this for two main reasons. First, when I need to change the design down the road I only have to to go the layout sketches and make adjustments. This keeps things simplier and less confusing. Second, when changes are made my over all assembly has a higher probability of success (less chance of issues) because it's referencing the layout sketches not the surrounding geometry. If you use a lot of split lines you'll immediately see the benefits of referencing the layout sketches.

Rob Rodriguez CSWP

http://www.axiscadsolutions.com

http://www.robrodriguez.com

http://designsmarter.typepad.com/rob_rodriguez/

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SW 2007 SP 2.0

 

[CorBlimeyLimey]

Question is, top-down.....or the skeleton approach

I'm confused! The "skeleton approach" is a major tool for creating Top Down designs. How are you differentiating the two?

Yes, skeletons can be used with Bottom Up parts to create hybrid in-context parts (which is my preference), but are they not effectively Top Down type constraints?

 

[J-C]

I have to have the sub-assys. And parts in the sub-assys need to be driven by other parts in other sub assys....or all from the top level.

By skeleton I mean a master part file with sketches, planes, axis, etc that is inserted into the component parts. Its likea backwards top down....no assembly required....at least you don't drive it from an assy.

Driveworks xpress may eventually come into play here....but for the current project, I need to just create a parametric sizable assy with parts.

Jason

SolidWorks 2007 SP3.1 on WinXP SP2