For my opinion better condition is:
<condition name="is_drawing">
<attribute name="epmdoc_CADName" regex=".*\.drw" />
</condition>
<condition name="is_part">
<attribute name="epmdoc_CADName" regex=".*\.prt" />
</condition>
<condition name="is_asm">
<attribute name="epmdoc_CADName" regex=".*\.asm" />
</condition>