code: public static float distancePointPlane(float pointX, float pointY, float pointZ, float a, float b, float c, float d) {
          float denom = (float) Math.sqrt(a * a + b * b + c * c);
          return (a * pointX + b * pointY + c * pointZ + d) / denom;
      }
docs: Determine the signed distance of the given point <code>(pointX, pointY, pointZ)</code> to the plane specified via its general plane equation
  <i>a*x + b*y + c*z + d = 0</i>.
  
  @param pointX
  the x coordinate of the point
  @param pointY
  the y coordinate of the point
  @param pointZ
  the z coordinate of the point
  @param a
  the x factor in the plane equation
  @param b
  the y factor in the plane equation
  @param c
  the z factor in the plane equation
  @param d
  the constant in the plane equation
  @return the distance between the point and the plane