Modifying legacy surfaces with GSM

This article describes how Advanced GSM was used to modify a design.

1. The model was originally created in Autodesk® Mechanical Desktop®, and imported via IGES into the think3 application.
   
   
    
2. The goal of the shape modification is to modify the edge of the model using the green curve as our initial condition and the red curve as the target condition.
   
   
    
3. Before starting Advanced GSM, we take a look at the surfaces to see what we are dealing with.
   
   The surfaces highlighted in orange are a total of seven surfaces, none of which have tangency or curvature continuity. We will simplify these surfaces before moving on to the desired shape modification.
   
   
    
4. We will replace the seven surfaces with a single Grid Lofted Surface — utilizing curves derived from the original model.
   
   
    
5. We also have some very messy surfaces "capping" the end of this part. These surfaces also should be simplified prior to initiating the desired shape modification. This capping situation is tough for any designer to model, however, we can actually use Advanced GSM to replace these bad surfaces with one very good one!
   
   
    
6. In order to cap the end of this part, we create a regular four sided planar surface and trim it to the approximate desired shape.
   
   
    
   
   

   Using the Surface Capping command You can easily cap the end of this part also using the Cappingcommand.

   
   
7. We initiate the Advanced GSM command, and select our initial curves (the edges of the trimmed surface) and our target curves (the curves on the model). In addition, we specify that the new capping surface created have both position and tangency continuity with the existing model surface. The resulting surface is a clean single surface, tangent to the U curve surface that we created earlier.
   
   
    
8. Now that the surfaces have been simplified we initiate Advanced GSM again to accomplish the original desired shape modification.
   
   
    
9. The selection list prompts for initial and target curves. In this case, the initial curve is the green curve and the target curve is the red curve. We choose to target position and select the surfaces to modify.
   
   
    
10. GSM gives the desired shape modification while maintaining all existing positional, tangential, and curvature continuities!