These movies cover some techniques for designing sheet metal objects in TouchCAD.
Sheet Metal Design (11.46 minutes) .illustrates how to use some of the relevant tools found in TouchCAD as they are or as a base for modeling custom objects based on them.
T-Tube Joints (5.11 minutes) illustrates some useful techniques when jointing T-tubes manually at any angle.
Background Image Modelling ( 7.43 minutes) illustrates how to model a 3D shape based on three in-scale background images. The model is a sheet metal based ventilation component.