When painting height in Substance Painter, you can carve and add. The built-in control (figure 1) let you go from -1 to 1. In reality, it's one gradient going from black (-1) to white (1). It's very similar to working with the overlay blending mode in Photoshop, where painting in any color below 128 will darken the underlying layer and any color higher than 128 will brighten it.
Basically, 0 height in Painter is 0.5 (designer) or 128 (Photoshop). Not a big deal really, but something to consider when creating height map, either while drawing in Photoshop or creating a procedural material in Designer.
In my matfx_heightAdjust graph, what i did was write a function that, as the height intensity value is lowered, increase the low value output and decrease the high value output of a level node, gradually bringing them toward 0.5. Simple but efficient.
In a future lab, i will go through the creation of the function itself, as it is a good example of an exposed parameter affecting multiple parts of a graph.