About Creating 3D Surfaces

Surface modeling provides the ability to create and edit associative and NURBS surfaces.

A surface is a 3D object that is an infinitely thin shell. There are 2 types of surfaces: procedural and NURBS.

Use procedural surfaces to take advantage of associative modeling, and use NURBS surfaces to take advantage of sculpting with control vertices. The illustration below shows a procedural surface on the left, and a NURBS surface on the right.

3D Surface Modeling

A surface model is a thin shell that does not have mass or volume. AutoCAD provides two types of surfaces: procedural surfaces and NURBS surfaces.

One typical modeling workflow is to create basic models using meshes, solids, and procedural surfaces, and then convert them to NURBS surfaces for additional shaping.

You create surface models using many of the same tools that you use for solid models: sweeping, lofting, extruding, and revolving. You can also create surfaces by blending, patching, offsetting, filleting, and extending other surfaces.

Choose a Surface Creation Method

Create procedural and NURBS surfaces using the following methods:

Understand Surface Continuity and Bulge Magnitude

Surface continuity and bulge magnitude are properties that are frequently used when creating surfaces. When you create a new surface, you can specify the continuity and bulge magnitude with special grips.

Continuity is a measure of how smoothly two curves or surfaces flow into each other. The type of continuity can be important if you need to export your surfaces to other applications.

Continuity types include the following:

Bulge magnitude is a measure of how much surface curves or “bulges” as it flows into another surface. Magnitude can be between 0 and 1 where 0 is flat and 1 curves the most.

Set Surface Properties Before and After Creation

Set defaults that control a variety of surface properties before and after you create the surface objects.