Gyroku

Gyroku is a solar shadow study tool built for architects, urban designers, and landscape architects who want to understand sunlight before they build. Place buildings, walls, trees, and poles on an interactive site plan, set your latitude and date, and watch accurate cast shadows sweep across the canvas in real time. The site editor lets you arrange up to 24 objects — blocks, towers, walls, poles, broadleaf trees, and conifers — each with configurable dimensions, rotation, and label. Drag the probe point anywhere on your plan and Gyroku sweeps every five minutes from sunrise to sunset, counting exactly how many hours of direct sun that spot receives. The Hub screen displays the result as a headline sun-hours figure alongside a solar-altitude arc, a shadow-ratio sketch, and a live sky silhouette. The Sky tab shows a full sun-path dome with today's arc plus summer and winter solstice references, a daily chart of shadow length, altitude, or sun hours, and an hourly table with altitude, azimuth, and shadow ratios. Day Study playback animates the entire day's shadow sweep on a single screen, complete with a phase-icon timeline from sunrise to sunset. Save as many named sites as you need in the Vault, attach a reference photo from your camera or library, and return to any study at any time. Gyroku uses standard astronomical equations — solar declination, the equation of time, and hour angle — accurate to well under one degree of altitude for any date and latitude. It is a study aid for early-stage design decisions, not a certified engineering or surveying instrument. Supports metric and imperial units, adjustable latitude presets, solar and clock time, and three shadow styles: Sharp, Soft, and Trail.