GoSeTwoCircles Definition    download .ghx

Computing tangency is easy if the circles are unconstrained. The centres of the two circles form a line. Move one circle along the line such that its centre is plus or minus its radius from the intersection of the line and the other circle. This situation is different --- the centre of once circle is constrained to lie on another, arbitrary line. The movement of the circle centre is governed by a parametric point-on-curve parameter t. The Goal Seeker adjusts this parameter until the tangency conditions are met. The Goal Seeker must operate twice: once for each tangency condition.     ... more on Design Patterns CA

GoSeTwoCircles Manipulations