9.5.2

1114 • CHAPTER 22
XPRESSO EDITOR • 1115
Dot Product
Here the dot product is used to calculate the angle between two input vectors. The following applies:
the dot product of Vector 1 and Vector 2 = the length of Vector 1 * the length of Vector 2 * the cosine
between Vector 1 and Vector 2.
The dot product, or scalar product as it is often called, calculates the projection of a vector onto
another vector. You can think of this as the shadow that is cast onto a sun dial, where one of the
vectors lies on the dial plate, the other vector represents the direction of the gnomon (the part that
points out and casts the shadow) and the sun is directly above the sun dial. This shadow corresponds
to the dot product of the two input vectors.
You can connect the two input vectors either way round to the Input 1 and Input 2 ports (the result
will be the same no matter which way round you connect the input vectors). The inputs must always
be vectors, but you can change the data type of the node itself in the Attribute manager. You have a
choice of Color, Vector or Normal.
FloatFunc
This node gives you direct access to a number of math functions and is especially useful when used
as an extension to the Formula node or to round values up or down. Choose the desired function on
the Node Properties page of the Attribute manager.
Exp
Calculates the exponential function of the input value.
Ln
In this mode, the natural logarithm is calculated.