DGKC Control Documentation

Skip Navigation Links.
Skip Navigation LinksHome Page > Deprecated > Deprecated Geometry > 3DS > Surface Patches Go to ActiveX docs Search Documentation

3DS Geometry

Z-axis of a 3DS geometry is a privileged one. All lines of the object are parameterized by the local z coordinate.

Every 3DS geometry has a Base. Base is an array of points on the object's axis ( z-axis ). We call these points Base Knots. A 3DS geometry has at least two knots: Minimal and maximal values of z coordinate for the object. Knots are used to define plot of different parameters of the model against axis of the object.

These plots are called Profiles. For example, x coordinate of a 3D Curve is a function of z coordinate. Its plot against z normally represented as a strip of lines (or arcs). Knots are points of z-axis where those segments are joined. For the default case of two knots, each such a strip will have only one segment. Adding extra knots allows creation of more complex geometry and approximation of any shape. Programmatically the set of knots is managed by IAxiBase interface. 

The simplest 3DS surface is a patch.  A patch is a piece of surface between two 3D Curved Segments.

When base of a 3DS has more than two knots, surface of the object consists of Patch Strips.

Surface of 3DS geometry consists of Patch Strips. Patch Strips are joined together by their edges. Edges of patch strips are 3D Curve Elements. In a sense surface of a 3DS object can be considered as a strip of Patch Strips.