- Download a free trial of T-Splines for Rhino. This fast-paced tutorial shows how to model a bathtub using T-splines v2 for Rhino, starting from input curves. For a 30-minute version of this tutorial, with more detailed explanations, and the .3dm of the tub go to Difficulty: Intermediate Commands used: Delete • tsAppend • tsConvert • tsExtrude • tsInsertPoint • tsManip • tsMatch • tsMerge • tsSelection • tsSymmetry