2017

(a) vertex 1 (b) tangents of vertex 1 (c) tangents of vertex 2 (d) vertex 2 (e) Reference point
Image courtesy of Topix
Extended bicubics have three types of points: vertices, tangents, and the reference point. Vertices and tangents
are collectively called surface points.
Vertices lie on the surface and its tangents determine the curvature of the deformation at each vertex. The
reference point indicates the axis of origin for applying rotation and scaling to surface points.
Use the surface points to control the deformation of the surface. Each vertex has tangent handles. By moving
the tangents and their handles, you can warp specific areas of the surface. You can translate, scale, or rotate
these points and tangents individually or as a group.
TIP If a tangent point is hidden behind a vertex or reference point, press Q and click the point in the image window
to select the tangent.
Tangent handles have three modes.
Indicates:This mode:
The handles are not broken. If you move this handle, the adjacent handle will move in the
opposite direction and by the same magnitude (length).
The handles are broken. If you move this handle, no other handles are affected.
The handles are geometrically continuous. If you move this tangent, the adjacent handles
will move in the opposite directions but maintain its magnitude (length).
Action Surfaces | 515