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It takes time to transform your ideas from napkin sketches to detailed Pro/ENGINEER assemblies. That’s the beginning of many a great thing, which ought to result in fabrication and a happy boss. Sometimes, though, you don’t need the entire assembly with all of the bells and whistles. Perhaps you are running a computational fluid dynamics analysis and all you need is a negative of your assembly. Or maybe you are designing packaging for a product, and need some nicely conforming foam to protect the device. Or else you just want a “light” version to use in continued work.
But just how best to get that “bare-bones” version? One way is to use your “selective suppression” to prune that model tree down to the trunk. You can, of course, start from the beginning, using what you can. There is another way—the unobtanium for your complex part blues is Shrinkwrap (Figs. 1 and 2)
Figure 1. Raw Assembly.
Figure 2. Exploded View.
So what is Shrinkwrap all about? For those of you who may not know about it, Shrinkwrap is a type of data structure that can manifest itself as a feature or model. It is cleverly covered up, almost hidden, and doesn’t get the widespread use of a solid or surface. The shrinkwrap feature is located under the Data Sharing submenu of the Feature menu.
As described by PTC, the Shrinkwrap feature is “a collection of surfaces and datum features of a model that represents the exterior of the model.” The advantages and applications of the Shrinkwrap feature are the ability to create minimally memory-guzzling representations of assemblies. These representations can be used to show subassemblies in parent assemblies and can handle control of dependency issues, geometry represented, and additional references.
The shrinkwrap model is an option available under the Save as umbrella. Again, as PTC describes it, Its function is to “share data with internal and external design groups and improve performance in large assembly design.” Some of the benefits the shrinkwrap model offers are the ability to represent complex assemblies with a single lightweight part that protects design intent and parametric data, and to improve performance of large assembly modeling in terms of load time. The proper-scale models can be saved as IGES, STEP, and VRML (for fly-throughs).
Just how do you customize your flavor of shrinkwrap to achieve your purpose? By tailoring the options, of course!
When you create your shrinkwrap, the first option pops right out at you, prompting you for the quality level. The level that you pick will control how well the shrinkwrap “wraps” to the original, ranging from 1 to 10. The increase in quality comes at a cost of longer creation time and larger file size (although it is still MUCH smaller than the assembly it represents).
The next item to determine—and a key one for these techniques—is whether to use auto hole filling. Regardless of its name, the auto hole fill option fills in cuts as well as holes, as long as they penetrate the entire wall thickness where they occur (so pockets need not apply).
Once you have made the initial dialog box disappear, you are presented with the remainder of the shrinkwrap elements. Of these, I find the Include datums and Geom dependency the most relevant here. Include datums lets you select datum planes, points, axes, and coordinate systems to bring over with the shrinkwrap. This capability is why, when the new component is created, the first feature is created as opposed to creating the default datums. The Geom dependency element determines whether or not your shrinkwrap is continually associative to its parent geometry. The way to go here is usually to make it dependent so that changes are carried downstream (Figs. 3-6, click to enlarge).
Figure 3.
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Figure 5.
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Figure 6.
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