Abs Scalar produces an absolute value from its input. In effect it turns all negative values positive.

Here is a cosine wave passing through a zero ground plane.

When we pass the signal through an Abs Scalar, all values below the zero plane become positive.

This method can be used to turn Perlin Noise...

...into Perlin Billows.

If there's any errors, omissions or questions about the above, please leave a comment and we will add further details in this post when relevant.

https://planetside.co.uk/wiki/index.php?title=Abs_Scalar