Hi Dwayne,
We use ProE's skeleton functionality to make very robust assemblies that allow different people to work on separate areas in a product. We use the skeletons for a three main functions:
Interfaces; between parts and subassemblies (typically datum features such as axes, planes, coordinate systems, curves and also Surfaces).Product Shape; Industrial design (mainly curves and surfaces) [we use this instead of the old master model method].Space claims; Bounding volumes and surfaces (typically Surfaces). Can be used for defining something like module space or assembly clearance. I seem to remember PTC's example is of a car with space claims for suspension and the like.
In earlier times we used skeletons at every level and while this is a valid technique it involved more overhead for us so we now use mainly a top level skeleton and only add subassembly skeletons if there is something that is specific to that level.
We use two methods of assembly in design. The more common is default location for the parts that are really dependent on the Skeleton for things such as shape and locations of fixing holes etc. For other parts (e.g. fixings) these are assembled to the skeleton rather than other parts. This makes the assembly totally robust; if any part is suppressed or removed the assembly still works fine as there are no interdependencies other than to the Skeleton.
Our big leap forward came about ten years ago when we went from just using Copy Geom in the parts to get features from the Skeleton to use to using Publish Geom in the Skeleton and picking these Publish Geom when making the Copy Geom in the parts. This later method allows for redefinition of the Skeleton Publish Geoms and reliable propagation (regeneration) throughout the assembly.
For those that think the skeleton gets quite complex; you are correct. A recent example product had some 450 features in the Skeleton. The Skeleton also needs to be carefully managed as the changes here do affect the rest of the assembly and if Designers are not aware that changes are being made then this can cause serious grief (but then so can many other methods of controlling design change). Of course only one person can work on the skeleton at one time otherwise you get problems here too.
We did look at integrating Layout functionality with Skeletons but it seemed to only add overhead in our applications so we use Skeletons as the total driver.
This works really well for our type of product. If you have products that require a high degree of reuse across a range then the complex skeletons we use may not be suitable but the more simple functions may still be of value.
Note; we found some years back that using solid geometry in a Skeleton caused problems so we only use Surface features and Datum features.
Regards, Brent Drysdale
Regards, Brent Drysdale
Mechanical Designer
Tait Electronics Ltd (www.taitworld.com)
New Zealand
Ph. +64 3 358 1093
Dwayne Wade wrote:
Hello Gurus!
My company is attempting to use 'spaceclaims' to manage design space available for different systems.
How does your company create and manage 'spaceclaims'? What are advantages and dislikes of using spaceclaims? Do you use skeleton parts to create a spaceclaim? Do you use a skeleton to manage both the spaceclaim and actual system?
Thanks for your insight,
Dwayne Wade
General Dynamics Land Systems
Wheeled Vehicle Systems Engineering & Design
Product Designer II
(586) 825-4718
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