From Valve Developer Community
The QC commands $pushd and $popd 'push' and 'pop' directories to and from the QC's active folder. Multiple
$pushd can be nested inside each other, so long as there are a corresponding number of
$pushd <path> ... $popd
$modelname "props\fan.mdl" $cdmaterials "models\props\" $model fan "fan.smd" $pushd ".\new animations\" $sequence rotate "rotate.smd" $popd $sequence idle "idle.smd"