A term used to describe the problem in 3D rendering where the same pixel is rendered onto multiple times. Particularly a problem when software rendering is used.

Overdraw can be reduced, and sometimes mostly avoided, using visible surface determination, however most rendering techniques still end up with large amounts of overdraw, particularly if Z buffering is depended on too heavily.

This problem is what makes the transparency 'cheats' present in some video drivers possible.

O`ver*draw" (?), v. t. [imp. Overdrew (?); p. p. Overdrawn (?); p. pr. & vb. n. Overdrawing.]

1.

To exaggerate; to overdo.

2. Banking

To make drafts upon or against, in excess of the proper amount or limit.

© Webster 1913.