Surface of Revolution
Surface Of Revolution geometry (SOR) is constructed by rotating a 2D segment strip in plane of
x and z coordinates (Generatrix or Profile Curve) around z axis.
To modify an SOR object programmatically query IStrip_DG
from IEntity_DG
of the object. Elements of the strip can be either straight or curved segments.
Straight segments have no parameters. They are modified by changing its end
joints, obtained form the IStrip_DG. Curved segments
have single parameter - curvature, which is either 0 or 1.0/Radius. Joints of an
SOR strip are 2D points and hence have two parameters. To see a sample of the
above manipulations open Pipes.mdg or Sphere.mdg in
MiniCAD sample and step though the
source code in a debugger.
Structure of the generatrix strip can be modified (elements added or
deleted etc) with the help of IStrip_DG.
In case of a cylinder, cone or any other SOR with an open generatrix
strip the discs at the top or bottom of the object can be removed or added with
the help of IBoundary
queried form IEntity_DG
of the object, thus rendering the object either as surface or solid.
Note that when the generating strip consists of a single point the object
will be an isolated circumference in x and y plane of the local axes. When
the strip has no elements graphically the
object will be represented only by the local frame of axes.
|