... providing a method in Templot for users easily to check if they have allowed adequate clearance. The spacing-ring tool is useful, but only if you know what size to set it. So in the next TDV update there will be a new feature to place a dummy vehicle on the control template and move it along the track by mouse action. The corner clearance between two vehicles can then be checked visually or by means of the spacing-ring tool. The controls will be added to the spacing-ring dialog: 2_231502_110000000.png I'm still working on this, hopefully some screenshots tomorrow. regards, Martin. posted: 20 Feb 2012 23:33 from: Dellboy Martin Awaited with great interest as this is an old chestnut and suffers much from confusing if not misleading advice. The 'dummy' approach sounds promising! posted: 21 Feb 2012 00:07 from: Tony W Hi Russell. "The formula I use provides the same result as you quote for end throw but mid throw will not necessarily be the same value" Accepted. It depends ...