[rwest]

Originally Posted by CelticNHBlue

Only because I'm an engineer:

Geometry dictates that three points define a plane, no physics is involved. Therefor the umpire, plate, and 1B are always in the same plane, no matter where you stand. However hp and 1B may not be along your line of sight, as you stated.

I agree, you can not definitively see both if they occur simultaneously, even if you stand first base line extended. Touching hp is the primary call, pulled foot is secondary for the plate umpire.

You haven't called on some of the fields I have had to call on. Sometimes home and first are definitely on different planes! LOL!