Bezier Triangle Tool
A tool to create and edit nonrational and rational Bézier triangle surfaces.
Bezier Triangle Tool

Use the Bezier Triangle Tool to model smooth triangular surfaces that can be scaled indefinitely, allowing for more natural and intricate surfaces.

Useful to design structures that do not possess a notably rectangular structure, and rectangular patches are therefore not a natural choice for modeling these complicated geometries. They lend themselves easily to patches on spheres or quadrics.

You can find the Bezier Triangle Tool in the Draw menu, as well as in the Right Mouse Context Menu once a Bezier triangle created/edited using this tool is selected.

Draw->Bezier Triangle will draw a default rational Bezier triangle around the origin and put you into the editing tool for the newly drawn surface.

Selecting an existing Bezier triangle drawn/edited with this tool and using Edit Bezier Triangle in the Right Mouse Button context menu will also activate the editing tool for the selected triangle.

To change the weight of a non-end control point, hover the cursor over the control point you want to change the weight of so that it is highlighted in green, type the new weight you want for it, without moving the cursor away from the control point, and press enter or return to influence the shape of the triangular surface.

The editing tool also allows you to select either one of the 10 control points or one of the 18 lines of the control grid that can be moved to manipulate the Bezier triangle to be the way you want it to be.

Inferencing is available when the selected point is moved along with inference locking using the Shift key. Hitting the Esc key during a move will reset the surface to the way it was before the move started.

Also, shamelessly plugging a paid extension of mine, you can use Rational Bezier Surface Properties to modify the surface(s) further if required.