Reading your drawing
The perspective doctor
Perspective is the part of drawing that rewards patience and punishes guesswork. A wall that leans a degree too far, a table edge that misses the vanishing point by a hair — invisible on their own, and together the reason a finished piece feels subtly wrong without anyone being able to say why.
Perspicacity looks for exactly those. It finds the vanishing point your own lines already imply, works out the rule each edge is meant to follow, and shows you the few places where the drawing pulls away from itself. Uprights are checked as uprights. Receding edges are checked against your vanishing point. Circles are checked against how far they sit from your eye level.
What comes back is not a score. It is a handful of marks on your own drawing, in the places a tutor would have pointed, with the corrected geometry drawn beside them so you can see the difference rather than take it on trust.
It is deliberately quiet. Lines that could reasonably belong to two rules are left alone, because guessing at your intent and calling it a mistake would teach you the wrong thing. Roof slopes, braces and ramps sit at their own angles and are never graded. And when a drawing has no vanishing point at all — an isometric room, a curvilinear sketch — it says so rather than inventing a reference to mark you against.
Bring a work in progress. It is easier to move a wall before you have rendered it.