Achieving Curved Mouldings
Hi Stu,
hope this helps, would not use terminology that you have, but to develop concentric rule or hidden rule,the running mould is constructed to enable it to run across the plain of a curved surface.a similar technique to running a moulding for a spiral staircase. The setting out is the key to all fibrous plasterwork, so a good knowledge of geometry would give you a sound base.
Unfortunately upload of picture keeps failing file:///Users/adamaitken/Desktop/IMG_1952%202.jpg