pRegion->getAreaProp()

I want to let the user draw a complicated, 2D polyline, select it, and have it convert to a region so I can use the mass properties for a handful of tasks.  I've gotten to the point (following the samples) where I am able to create the region using

es = AcDbRegion::createFromCurves(curveSegs, regions);

AcDbRegion *pRegion;

pRegion =static_cast<AcDbRegion*>(regions[0]);  // I only have one element to pick

pRegion->getPlane(plane);

plane.getCoordSystem(origin, xAxis, yAxis);

es = pRegion->getAreaProp(origin, xAxis, yAxis, perimeter, area, centroid, momInertia,

prodInertia, prinMoments, prinAxes, radiiGyration, extentsLow, extentsHigh);

Then I save it to the database.  It works fine up to this point, but I get the wrong centroid (and different than the command line "MASSPROP")

Anything obvious?  Any help would be appreciated.

Thanks,

Ed