Hi, A couple more questions if I may. The attached PDF basically sums up my problem - I'm trying to construct a data-driven drawing, but it may be a case of "running before I can walk". I'd like to be able to control the various features I've marked up by variables, but up until now have not had much luck - whenever I try to change a diameter etc using variables, everything becomes a mess... Am I going about this the wrong way? Thanks for any help/pointers! Cheers Nick
Nick, Keep in mind that dimensions are variables. Dimensions drive the geometry. 1. For the notch widths define equal constraints between the lines at the bottom of the notches. You can do the same for the notch depth lines. Place dimensions for the depth and width of one of the notches. The other notches will adjust with the the one with the dimensions when you change the dimensions. 2. Place a diameter dimensions to control the diameters. 3. The number of semi-circles cannot be controlled by variable. 4. The gap between the semi-circles can be made the same by using the equal constraint on the lines again. 5. You can control the position of the first semi-circle by placing a distance between dimension to drive the location. 6. you can use horizontal alignment constraints to ensure the circles align with the semi-circles. Regards, Rick B.