Monsoon opened this issue on Mar 19, 2010 · 165 posts
eonite posted Thu, 01 April 2010 at 11:52 AM
A noise node outputs numbers. Imagine an infinite 3D space and this noise node assigns a value to each point in this space. Often it`s a value between -1 and +1. The result is a (random) pattern accross this 3D space.
Now, when you connect a Composer 3 node to the output of for example a noise node you transform numbers into vectors.
A vector has a magnitude and a direction. Vectors are not directly visible but, as you can see the effect in our example.
2-This is a Math Pattern Line node. Just like the Nose node, they output numbers. This node in specific outputs numbers that result in a line pattern.
3- This is a constant vector node, which is connected to a multiply node along with the output of the composer nodes. This way you can conveniently determine the the direction and magnitude of the vector. This constant node has 3 input fields, one for each dimension.
4- It`s a Combiner node in "Add" mode. I added it, so I could mix the output of the Line Pattern node with the (unconverted) output of the Noise node (1).
As you can see, the Multiply node (which outputs a vector) is conncted to the Origin parameter of the Line Pattern node (2). This allows the vector to "disturb" the pattern generated by the Line Pattern node.
Now what is important, when you experiment with this function, is to observe the preview of this Line Pattern node. You will be able to directly see the effect the vector has on the pattern.
Check out how entering a value into one of the input fields of the Constant Vector node effects the pattern. Try to understand what happens there (for instance entering a value into Input field X will affect the line pattern by pushing the pattern in the x-direction (depending on the value of the vector at a given point)
Its not really easy to explain. Its best if you experiment untill you are familiar with it. It`s easier than it sounds.
Note: This technique is not really very important when you build Displacement functions. But it can for instance be helpful when you have a node that generates straight lines/borders and you want to get it to look more natural.
Note 2: Instead of using a nose node and converting its output into a vector you could of course use a Turbulence node (which already outputs a vector). One of the reasons why I`m using Noise/Fractal Noise nodes and convert the into vectors in order to apply Turbulence is because this way I have the option to also use the unconverted output.*
I hope it was not too confusing 