code: @Pure
  	public static boolean intersectsSphereSphere(
  			double x1, double y1, double z1, double radius1,
  			double x2, double y2, double z2, double radius2) {
  		double r = radius1+radius2;
  		return FunctionalPoint3D.distanceSquaredPointPoint(x1, y1, z1, x2, y2, z2) < (r*r);
  	}
docs: Replies if two spheres are intersecting.
  
  @param x1 is the center of the first sphere
  @param y1 is the center of the first sphere
  @param z1 is the center of the first sphere
  @param radius1 is the radius of the first sphere
  @param x2 is the center of the second sphere
  @param y2 is the center of the second sphere
  @param z2 is the center of the second sphere
  @param radius2 is the radius of the second sphere
  @return <code>true</code> if the two shapes are intersecting; otherwise
  <code>false</code>