The two sets of faces for blending are conventionally called the right and the left wall. In most general case, these can be arbitrarily positioned in space and have arbitrary geometry of the surface. The system constructs the blend surface between the right and the left wall in several steps.

Step 1 |
Step 2 |

Step 3 |

•First, the set of planes is computed for holding the blend cross sections. The position of each plane depends on the existence and the shape of the auxiliary direction guide, as well as on the computational algorithm of a particular blend type. One can specify various blending effects by manipulating the orientation of the cross section planes.

•Next, two points are defined on each plane that will be the bounds of the future blend surface. One point belongs to the right wall, the other – to the left. These will be referred to as the points of contact of the blend surface. The sets of the points of contact on the right and left walls make the two lines of contact. The position of the points in each cross section depends on the shape and mutual situation of the walls, as well as on the computational algorithm of the particular blending mode.

•Finally, the system computes each cross section of the blend surface spanning the two points of computed in the previous step. The shape of the blend cross section depends on the positions of the points of contact and on the selected geometrical algorithm.

•The final result may also be affected by a number of additional options and boundary conditions.