... this kind of thing is driving me nuts. In the attached file I am attempting to create a transition from the straight track to the curved one. Both sections of track are aligned on the background scan how I want them. Clicking on the straight section and selectiing transition causes Templot to tell me it can't do it- WHY? Hi Bruce, A transition is mathematically impossible here because the track centre-lines are overlapping. In order to create a transition there must be a gap between the tracks before you start. 2_110305_280000000.png If you put the fixing peg at the top end of the control template, and then reduce the radius slightly (F6 mouse action) until there is a gap between the centre-lines, it will then be possible to create a transition curve between them. The larger the gap, so the longer will be the resulting transition zone. There is a tutorial explaining this at: http://www.templot.com/martweb/info_files/make_trans.htm It can be helpful to temporarily change the control template to a centre-line ...