The Creative Inventor: Boss, I Shrunk the Files!

No, Autodesk does not have an electro-magnetic shrink ray like in the movies, but it does have a powerful tool in Autodesk Inventor 2010. Shrinkwrap has the ability to improve large assembly speed and reduce file sizes of complex part files such as automotive castings. Introduced as a Autodesk Labs add-in in Inventor 2009, the 2010 version has been improved and expanded to become a powerful tool.

How it works

Shrinkwrap works by reducing the number of faces in a part or parts within a subassembly. The image below shows the Reciprocating Saw.iam from the \Inventor 2010\Tutorial Files\ folder. Note that the inset in the image shows that there are 20 components in this assembly under the Master Level of Detail. If this subassembly comprised thousands of components, then this number would be much larger and performance would be severely affected.”

In the next view shown below, I have switched to a previously created Substitute Level of Detail. This level of detail was created by applying the Shrinkwrap command to the original subassembly. Shrinkwrap is very similar to derived parts, where multiple parts in an assembly are combined into one part. You'll notice that the same assembly as shown in the first image has now been reduced to an absolute minimum. The part count has been reduced to one, and total files reduced to two.

The default shrink-wrapped setting produces a surface model file that retains all of the colors of the original parts. Any interior faces do not exist in the shrinkwrap, greatly reducing the file size and graphics processing requirements.

Once you have created this new Level of Detail, you can easily toggle quickly between this shrink-wrapped representation and the actual original subassembly file. So, with Inventor 2010 you have the best of both worlds - and you can use both to your best advantage. The created shrinkwrap component is usable in other designs for placement purposes and measurement without impacting memory on slower machines.

How to create a Shrinkwrap

Creating a shrink-wrapped component is much simpler than creating a derived part. The component is created from inside the assembly file, eliminating the need to derive the assembly into a new part. Not only is it all done automatically, but the substitute will normally be much smaller than the original derived part approach.

Here are the steps:

  • Select the Shrinkwrap command from inside the top assembly. The following dialog will appear, allowing you to create the shrinkwrap part.

  • Because you are creating a shrinkwrap from the top level assembly, the command will assume, by default, that you want to shrinkwrap all of the parts and subassemblies that exist at the top level.

  • Don't worry as you progress through creating the shrinkwrap - you will be presented with the Derived Assembly dialog box where you can choose which parts and subassemblies will be added into the shrinkwrap.
  • Once you have accepted the settings in the Derived Assembly dialog and picked OK, not only will the shrinkwrap be created as an individual IPT, but a new Substitute Level of Detail will be added at the top assembly level.
  • Be absolutely sure to pick Save at this point to ensure that the Substitute Level of Detail is saved in the assembly.
  • After saving, you will find the you can quickly toggle between the original assembly Master Level of Detail and the shrink-wrapped Substitute Level of Detail. During the save, the new shrinkwrap part file will also be saved.

Simple, wasn't it?

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