How can you modify a model without history? Use the SOLIDWORKS direct modeling tools to reverse engineer an existing model. When you need to create tooling or fixtures for your customer parts, it is often necessary to remove all the details that will not be produced by your tooling, or features which are simply not required for modeling your fixture.
This process becomes more complicated when the model you receive from your customer has been created with different CAD software. That means you will import only the geometry of the part, without the feature history that created it.
Reverse engineer/model an imported part
Trying to reverse engineer the part in order to discover how the model has been created is detective work. Less experienced SOLIDWORKS users will try to guess how the part looked early in the modeling process by adding or removing material, using features such as the Extrude-Boss or Extrude-Cut. This can be a very tedious process, with a result that is quite different from the actual geometry.
The SOLIDWORKS users who know how to manipulate “the very fabric of SOLIDWORKS”; people who most likely graduated from either the Surface Modeling or the Mold Design Tools courses at Javelin, would apply a much more elegant technique. They would take advantage of the underlying fabric of the existing faces in order to patch the areas that are missing.
These advanced SOLIDWORKS users know that when faces are deleted, the surrounding faces can be untrimmed until they meet to form new edges, practically re-creating a “younger version” of the part during the manufacturing process. And since the untrimming operations such as the Untrim, Delete and Patch Face(s) and Delete Hole commands are revealing the actual surfaces that had existed before the customer cut his holes, the resulting geometry is very precise.
Please watch this video for a demonstration of this technique on a very interesting model posted on the SOLIDWORKS Forum by Skyler Morris:
If you need to modify existing geometry, please review an interesting case study about Direct Editing an imported body using SOLIDWORKS.