Shape description is a collection of surface and solid modeling, analysis, and 2d and 3D sketch commands.
With these commands, you can design parts that are aesthetically pleasing by including complex geometric requirements that extend beyond simple prismatic shapes.
Shape description provides:
Use the Sculpt command to add and remove material from an existing solid body, or to create a new solid body based on untrimmed surface geometry. Sculpt works on a wide range of geometry in a surface or mixed surface and solid environment.
You can select surfaces and work planes as bounding geometry for the sculpt operation. In addition, Sculpt implicitly uses existing faces of solids to designate possible boundaries. Sculpt cannot fill or add material in infinite space. Therefore, the surfaces, together with any pre-existing part, must create a closed, water-tight region.
In the Extend command, you make surfaces larger in one or more directions.
When you select the method to terminate the extension, it is a good practice to use Distance termination extent when possible. If the model changes and you terminated on a specific face that no longer exists, you must recreate the extension. By specifying a specific distance, the extension remains intact.
In the Trim command, you select a cutting tool to remove surface areas.
If you select a curve as a cutting edge that does not fully intersect the face, it extends automatically. A surface that does not fully intersect the surface extends automatically.
If edits to the cutting tool or the surface bodies selected to be trimmed change how the cutting tool intersects the bodies, the trim recomputes
If edits cause the cutting tool to intersect new surface bodies that did not exist in the initial selection set, those surface bodies are not trimmed.