Every time I watch a video and there is math node I get completly lost because i can´t tell what is happening. Please someone can you post a video where it is explained or tell me what is going on.

The math node just outputs the operation you have chosen, to the inputs.

**Add** will add both inputs, **multiply** will multiply them, etc.

The top input has preference, so operations like *is greather than* outputs 1 if top input is greather than bottom input, and 0 otherwise (some operations only use the top input!).

Depending of the values that you plug into you input, you’ll get different values in the output. Which makes all nodes to act like an equation that uses the inputs as variables.

For example, using the math node to multiply the X component of a vector (input 1) with a value of 2 (input 2), will output the double of X (scaling x by 2); Something like F(x) = 2x.

Now, for every sample that calls the nodetree, there are variables that are inherent to the point being shaded (coordinate vectors, normal vectors, vertex colors, ray states, etc)… And for each sample, those variables are ‘placed’ in the node tree, and the output value/colors/closures are calcultated.

Thanks for that. I thing i understand it little bit better. I will try some things in Blender and see what will happend.