Sciography, also spelled sciagraphy or skiagraphy (Greek: σκιά "shadow" and γράφειν graphein, "write"), is a branch of science of the perspective dealing with the projection of shadows, or delineation of an object in perspective with its gradations of light and shade. One of the major professional fields that use this technique is the architectural field. In architecture it is defined as a study of shades and shadows cast by simple architectural forms on plane surfaces.
In general sciography the light source is imagined as the sun inclined at 45 degrees to both vertical plane and horizontal plane coming from left hand side. The resultant shadow is then drawn.