2009

A typical application of Shape Mark would be to leave marks after particles

impact objects in the scene. For example, when a torpedo hits a boat and

explodes, you could use Shape Mark to leave scorch marks on the boat surface.

TIP By default, the mark left by Shape Mark is always rectangular, no matter what

shape the particles are. To leave a differently shaped mark, choose the Shape

group > Rectangle option, and use a material on page 2918 in the same event with

transparent areas to define the mark's outline. For example, apply a Mask map to

the material's Opacity channel, and to the map's Mask channel, apply a bitmap

containing an alpha channel. On the Bitmap Parameters rollout, set Mono Channel

Output to Alpha.

NOTE With its default settings, the Shape Mark operator can generate coplanar

faces, which the mental ray renderer cannot render well. If you want to use mental

ray rendering with Shape Mark, adjust the operator's settings as follows:

■ In the Shape group, choose Box Intersection.

■ Set Surface Offset to 0.01.

■ Set Offset Variation to 0.005.

■ Set Vertex Jitter to 0.002.

With these settings, faces are no longer coplanar, and the mental ray renderer

gives better results.