← artdaily

Ellipse Orbit

draw clean ellipses inside their bounding planes

round
score
best

Loading…

Drawing an ellipse that fills its box

Five dashed boxes come up one at a time, ramping from near-circles to slim ones. Draw the ellipse that touches all four sides — accent ticks show where — starting anywhere on the curve and going the whole way round. One trip round a desktop box covers about 900px, roughly three times what a trackpad can throw in a single contact, so lifting is expected — put the pointer down again close to where it left off and the same loop continues. Under 75% of the way round, nothing is scored — the loop waits.

An ellipse is not a shape to memorise but a circle seen at an angle, and the box decides the angle. The reveal makes that literal — a real circle of the box’s major radius rotates in 3D about the major axis until, at a tilt of acos(minor ÷ major), its projection is the ellipse asked for. How far it turned is that ellipse’s degree, the term art instruction uses everywhere without explaining. Wherever your stroke wandered widest of the truth, the reveal draws a ring, so the correction is a place on the loop rather than a number.

What the loop is judged on

Before anything is measured the stroke is respaced evenly along its own length, so a quick orbit and a slow one are read as the same geometry. What is left is distance: how far each of your points sits from the true curve, in pixels. Coverage multiplies that fit, so a gap costs more than a wobble, and an unclosed loop takes off as much as 10 points — the flash label names which of the three pulled the number down. Zero comes at 14px, or at 18% of the box’s mean radius when that is bigger, times 1 on a pen, 1.5 on a finger, 2 on a mouse or trackpad; the pixel floor is what keeps a phone-sized canvas from asking finer work than a desktop. The first 9% of that band costs nothing, so a clean loop lands on 100, and a round is the average of its five boxes. No AI reads the drawing — every point of your stroke is measured against the ellipse the box defines, and the score is what those distances average out to.

More line & hand drills: Full Circle · Draw Through · Mirror Mirror · Angle Snap · the whole catalogue