Surfaces
List of: Discussion Topic
Subjects: Construction Geometry, Model Geometry
Contents: Fundamental Concepts

Surfaces can be planar, cylindrical, conical, spherical, toroidal, or sculptured. Cylindrical and conical surfaces can be circular or elliptical.

ACIS supports these general types of surfaces:

Analytic surface A simple surface that can be wholly represented by a simple algebraic formula. Simple analytic geometry can generally be analyzed up to, but not beyond, the fourth degree equation.

Spline surface A surface that cannot be directly represented in ACIS by one of the simple analytic surfaces (i.e., by a simple analytic formula), but which can be indirectly represented by an ordered list of analytic formulae, by segmenting the curve or surface with control points.

The surface class is the base construction geometry class for surfaces, and other surface construction geometry classes are derived from it. The surface class is abstract construction geometry, while its children are specific construction geometry.

The following classes are derived from the surface class:

plane Defines a planar surface.

cone Defines a cylindrical or a conic surface, both of which can also be circular or elliptical.

sphere Defines a spherical surface. It mathematically defines a sphere in both xyz object space and in uv parameter space.

torus Defines a toroidal surface.

spline Defines a sculpted surface. This is a surface beyond the scope of a simple analytic surface.

stripc This special surface class defines a strip curve, which is a surface defined in a neighborhood of and passing through a given object-space curve.

There are model geometry classes (with uppercase names) that correspond to these construction geometry classes. The SURFACE class is the base model geometry class for surfaces, and other surface model geometry classes are derived from it. The SURFACE class is abstract model geometry, while its children are specific model geometry.
PDF/FCG/07CRVSRF.PDF
HTM/DATA/ACIS/FCG/07CRVSRF/0004.HTM