void setGridLimitsForAtom(Point3f ptA, float rA, Point3i pt0, Point3i pt1) {
		xyzToVoxelPt(ptA.x - rA, ptA.y - rA, ptA.z - rA, pt0);
		pt0.x -= 1;
		pt0.y -= 1;
		pt0.z -= 1;
		if (pt0.x < 0)
			pt0.x = 0;
		if (pt0.y < 0)
			pt0.y = 0;
		if (pt0.z < 0)
			pt0.z = 0;
		xyzToVoxelPt(ptA.x + rA, ptA.y + rA, ptA.z + rA, pt1);
		pt1.x += 2;
		pt1.y += 2;
		pt1.z += 2;
		if (pt1.x >= nPointsX)
			pt1.x = nPointsX;
		if (pt1.y >= nPointsY)
			pt1.y = nPointsY;
		if (pt1.z >= nPointsZ)
			pt1.z = nPointsZ;
	}