Yunus Balcioglu

float height = ch("height");

string primgroups [ ] = detailintrinsic ( 0, "primitivegroups" );
foreach ( string group; primgroups )
{
    vector center = getbbox_center ( 0, group );
    if ( center.y < height )
    {
        int prims [ ] = expandprimgroup ( 0, group );
        foreach ( int pr; prims )
            removeprim ( 0, pr, 1 );
    }
}