Spring 2002
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Pro/ANATOMY
Modeling Body Parts In Pro/ENGINEER®
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Key Tools for Anatomical Surface Modeling

Here’s a list of some Pro/ENGINEER tools that I found most useful in prosthetic modeling. You must have Pro/SURFACE® to access some of these features, since you cannot create this sort of geometry directly in solids.

• Datum planes, points and curves establish the framework for your surface model and control the desired motion and size/shape control of the subject (Fig 2).

Figure 2.

• Sketched spline datum curves give both control and flexibility to a parametrically driven surface model. Spline points can be dimensioned, aligned to existing datum points, or left free to find their own way during parametric manipulation. Figures 3 and 4 show how a surface built over spline datum curves can be designed to handle variations in heel height.

Figure 3. Figure 4.

• Thru point datum curves are great for connecting vertices in 3D space to help smooth out surfaces. Tweaking gives added control of the surface between known vertices.

• Projected datum curves are useful when you want to sketch a surface boundary that does not fall on a flat plane.

• Approximate composite datum curves get rid of unwanted curve vertices and break points that cause segmented surfaces.

• Surface by boundaries (SBB) stretches out the skin once the framework is complete, and allows you to control the fit to neighboring surfaces. WARNING: This feature also lets you know very quickly how well you did (or didn’t) construct your datum curve framework. You may have to go back to your framework several times to get the desired results in your surface.

• Surface merge, trim, extend and transform bring all those surface boundaries together. Use transform tools to mirror geometry for bilateral symmetry. The goal is to get a contiguous surface model and ultimately a solid model.

• Surface analysis lets you visualize your finished surface to expose kinks and bends that may otherwise be hard to catch in the screen display of the model.