Painterly Rendering for Animation The author starts with the assumption that painterly rendering is necessary or desirable. Most of the Introduction is spent justifying this point of view. The second assumption is that current techniques are inadequate.

This technique solves 2 major problems with current approaches 1.The “shower door” effect. 2.Lack of frame-to-frame coherence. Both of these effects result from the fact that brush strokes are not positioned based on constant locations in Model Space.

Past Research 1.Created still images using brush strokes generated from 2D source pictures. [Haerbli] This does not allow for usefull frame-to- frame coherence (must be totally random or “stuck” to view-plane).

Past Research continued 2.Particle Rendering, which has been used before [Reeves], rendering particles in Model Space as simple 2D elements in Screen Space. This has not been used before for creating painterly images.

Brush Attributes Image – typically a monochrome bitmap. Color – obtained from a smooth-shaded rendered image. Orientation – determined by a 3D-to-2D projection of surface normals OR surface parameter. Size – scalar values are maped to a range of predefined sizes. Position – determined by particle’s position in Screen Space.

Future Directions In many cases single brush strokes are a very effective way of abstractly rendering repetative elements i.e. tree leaves. The brush stroke size could be made constant relative to the screen surface. Particle placement could be improved. The brush strokes could be lengthened and deformed to follow curves.

Conclusions That two previous rendering methods have been successfully brought together to solve the two major problems of “shower door” effect and frame-to-frame coherence. The painterly algorithem produces images with effects similar to those used by impressionist painters.