| OCR Text |
Show 133 their effect thus the direction the on reflected) light deviation of position of the average good effect a perturbation small before the orientation of in (relative the surface to The normal in terms of The value value of of the and base the patch normal by of is the from to get normal perturbation independent of normal be the same must amount orientation the a performs surface This the on of viewer. perturbation function function which function will derivatives is and independent defined vector at not x = X(u,v) Y = Y(u,v) be. (u,v) Z Z any point is Yu Zv Yn = Zu Xv Xu Yv - - - the prime by = will Zu Yv Xu Zv Xv Yu be derived ripples F(u,v). small but the component in the negligibly be might Xn Zn defines (the perturbation of the normals) the is, direction vector this That which the it (and surface therefore, formula. surface. surface) a its the effect the of that normal their function direction manner a than expect, intensity such same the to would the on surface portion of texturing a the in specified nudged the in it using be must having from the rather that We position. of The position of |
