Date: Sun, 24 Nov 1996 23:08:52 GMT Server: NCSA/1.5 Content-type: text/html Last-modified: Wed, 03 Jul 1996 20:04:20 GMT Content-length: 3635 Shadow Tip

Making Shadows.


Shadows are powerful perceptual cues for the 3D relationship of objects in a scene. The DX renderer does not produce shadows, but is possible to generate acceptable shadows by modifying the colors of individual vertices of objects in a scene. The macro described here performs the following steps:

This approach (a sort of vertex-mapped, z-buffer method) has some limitations:

The macro dialog box is shown below.
Explaination of inputs:

  1. The object input carries the objects to be shadowed against each other.
  2. The depth_resolution input is the resolution of the desired depth-buffer.
  3. The shadow_factor is the amount to "dim" a shadowed vertex.
  4. The light_pos is the direction to the light at infinity.
  5. The depth_ingore input is the threshold for self-shadowing. Set to zero, it will cause surfaces to "dim" themselves.
  6. The object_scale input overrides the automatic conversion of the object size to camera coordinate space.
  7. The offset input allows the objects to move along the z-axis of the light.

To download the test program click here. . You also need it's configuration file from here.

The test program layout is shown here.

An example output from the program is shown below.

To download the macro click here.

Another example is shown below. A protein ribbon representation is casting shadows on itself and on two planes.


See also: