center method
void
center()
Center the geometry based on the bounding box.
Implementation
void center() {
computeBoundingBox();
boundingBox!.getCenter(_bufferGeometryoffset);
_bufferGeometryoffset.negate();
translate(_bufferGeometryoffset.x, _bufferGeometryoffset.y,_bufferGeometryoffset.z);
}