float calcRotationRadius(Point3f center) {
		float maxRadius = 0;
		// XIE: we must calculate the rotation radius for the simulation box, which is a cuboid
		if (frameRenderer instanceof ExtendedFrameRenderer) {
			// maxRadius = ((ExtendedFrameRenderer) frameRenderer).cuboids.getRotationRadius(center);
			// if we do not calculate the above, there will be a jump when the first time we add an atom.
			// but if we do, there will be a lot of problems because the rendering seems to depend a lot
			// on the value of the rotation radius, which is only determined from the atoms.
			maxRadius = calcRotationRadiusForAtoms(center);
		}
		else {
			maxRadius = calcRotationRadiusForAtoms(center);
		}
		return maxRadius == 0 ? 60 : maxRadius; // XIE: 6 nanometers for empty box
	}