# Camera Data “View Vector” Interpretation

I am trying to develop some materials with interesting optical properties. In doing so, I am investigating the use of the "View Vector", however I do not understand it. Looking at the documentation, it says it is a (unit) vector pointing from the camera to the point on the object.

However, the following screenshot suggests something different. I would expect taking the dot product of the "View Vector" with the object normals should yield a value of 1 when the object surface faces the camera, and a value less than 1 elsewhere, specifically zero for parts of the object perpendicular to the camera viewpoint.

The 3 objects in the screenshot show a) behaviour different to that expected and b) seemingly inconsistent behaviour. What is going on here?

Thanks

• – cegaton Feb 25 at 21:31

• And just to confuse everything, if you ever use OSL, its I global variable points the other way from Geometry's 'Incoming' – Robin Betts Feb 26 at 12:17