$nodecal

$nodecal is a shader parameter for textures in Source games.

$nodecal 1 will stop bullet holes and other decals from applying to the textures flagged with it in their VMTs.

This is useful for materials that use $translucent^[Why?].

Important:This is a material map compile flag when used on materials designed for brushes and displacements, being written to the BSP as SURF_NODECALS.
It is a regular parameter when used on materials designed for models.