Module bridge 

Bridging a gap: a blend surface between edges of two faces, and a blend curve between the ends of two edges.

Both are Hermite constructions across the gap. Each side contributes its position, a crossing tangent pointing off its face (or along its curve) for G1, and the second derivative that matches its curvature for G2; the polynomial across is the Bézier of the least degree holding all of them.

The surface runs along the two edges in u and across the gap in v, with v = 0 on the first edge and v = 1 on the second. Its rows next to each edge are that edge’s own B-spline control polygon, made compatible with the other’s (the same degree and knots), so the edges lie on the surface exactly and are shared as they are, gaining a trim on the blend. The crossing derivatives along each edge are B-splines on the same knots, interpolated at the Greville abscissae. On a plane every interpolated tangent lies in the plane, so the join is tangent (and for G2 curvature continuous) exactly; on a curved face the join is measured along the edge and the knots refined until it is within budget.

Enums

End

One end of an edge, in the direction the edge is traversed: the start of a reversed edge is the end of its curve’s range.

Functions

make_blend_curve

Bridge the gap between the ends of two edges with a blend edge.

make_blend_surface

Bridge the gap between two edges with a blend face.