Sketch has two parts, light and dark, which are distinguished by the dividing line between light and dark. If the dividing line between light and dark is found, objects will have a sense of form and space. Bright parts include highlights, sub-highlights, gray and sub-gray, and dark parts include dark parts and reflections.

Generally speaking, the boundary between light and dark is the darkest part.

Perspective means near big and far small, near real and far virtual, near bright and far gray. It is recommended to read the basic sketch book and read it on the following website. If you can't copy it, you must read it yourself. There are various explanations at the bottom of the page.

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