Editing Normal (geometry) (section)

==Uses==
* Surface normals are useful in defining [[surface integral]]s of [[vector field]]s.
* Surface normals are commonly used in [[3D computer graphics]] for [[Computer graphics lighting|lighting]] calculations (see [[Lambert's cosine law]]), often adjusted by [[normal mapping]].
* [[Render layers]] containing surface normal information may be used in [[digital compositing]] to change the apparent lighting of rendered elements.{{citation needed|date=February 2020}}
* In [[computer vision]], the shapes of 3D objects are estimated from surface normals using [[photometric stereo]].<ref>{{cite web
  |url=http://users.eecs.northwestern.edu/~yingwu/teaching/EECS432/Notes/lighting.pdf
  |title=Radiometry, BRDF and Photometric Stereo
  |author=Ying Wu
  |publisher=Northwestern University
}}</ref>
*The normal vector may be obtained as the gradient of the [[signed distance function]].