$softwareskin

$softwareskin is a material shader parameter available in all  Source games.

Comparison of vertex compression on vs off on a high poly mesh.

When enabled, this parameter disables vertex compression. Useful on high poly smooth objects, which suffer noticeable artifacts with vertex compression on.

Note: Flexes are not supported with software skinning.

Warning: This comes at a performance penalty. Hardware acceleration is disabled, so use this sparingly, especially on high poly models.