As a constant double checker, I came hear to find out if what I learned and was teaching was incorrect.
From what I have learned here, I'm not convinced that this information about the D Plane has been trumped by the geometry of the circle but I am open minded.
John,
In the precision Sketch 2-C-1 #3 (2-N-0 / Geometry of the Circle with Separation deliberately assumed at Low Point), the Swing Path (Arc of Approach), the Clubface and the Line of Compression each face directly down the Plane Line (in this case, also the Target Line). TGM contends that this configuration will produce maximum compression (no "glancing force") and a dead straight shot.
Under these exact conditions, does the D-Plane concept predict another result? If so, what? If not, then in this specific instance, how does D Plane theory "trump" Geometry of the Circle / Hinge Action theory? Or vice versa? In a non-adversarial world, could they be equally predictive?