MbExtrusionSurface Extrusion Surface

The MbExtrusionSurface class is declared in the surf_extrusion_surface.h file.

The MbExtrusionSurface extrusion surface belongs to the group of swept surfaces MbSweptSurface. The extrusion surface is a special case of a swept surface with a rectilinear spine curve. The extrusion surface is described by the generatrix curve MbCurve3D curve, the extrusion direction vector MbVector3D direction, and the extrusion length distance.

The first surface parameter u coincides with the parameter of the generatrix curve. The first surface parameter takes values on the interval umin ≤ u ≤ umax, which corresponds to the domain of the generatrix curve. The surface can be periodic with respect to the first parameter if the generatrix curve is periodic.

The second surface parameter v takes values on the interval: vmin ≤ v ≤ vmax. The value v = 0 corresponds to a point on the generatrix curve; the value v = 1 corresponds to a point of the generatrix curve displaced by the vector direction * distance. The surface cannot be periodic with respect to the second parameter.

In the PointOn( double u, double v, MbCartPoint3D & s ) method, the position vector of the surface s is described by the vector function

\begin{equation} \mathbf{s}(u, v) = \mathbf{curve}(u) + \mathbf{direction} \cdot \mathit{distance} \cdot v \end{equation}

Figure shows the extrusion surface:

The following inequality must hold for the boundary values of the second surface parameter: vmin < vmax.