I would like to get the Volume Mass properties of an open BREP. The implied closed geometry would be between the BREP and it’s projection one of the world coordinate system planes (i.e. y=0 plane).

This is essentially the AreaMassProperties.WorldCoordinatesFirstMoments.Y, but multiplied by the j component of the normal vector, so the Integral of y * dm * j, x * dm * i, or z * dm * k.

I would also like to get a volume centroid, so integral of x * y * dm * j / volume for the X centroid, etc.

How would I go about this?