This is a normal map. A normal is the direction perpendicular to the center of a face, or can be averaged to a single vertex from the adjacent vertices.
Basically it fakes geometry by adding normals that don't exist on the original object.The colors are related to the change in angle. Don't ask me to explain the math
Its possible to convert grey scale image to normal maps, how useful it is depends on how the grey scale image was created. If the greys represent elevations from a surface then the results should be fairly good.
As near as I could tell, after a weekend geek-fest, a "normal map" is a pixel field in which grayscale values are raised perpendicular to the image plane, by some (tunable) value. The reasons behind the garish color scheme, though, still elude me. In any case, the game development community has wrestled with these conversions for some time; an online search can take one into codes and various freeware that can do this conversion. However, nVIDIA provides a Normal Map Creation Filter Plug-in for Adobe Photoshop that can turn grayscale images into normal maps, using all manner of controls, including the Alpha Channel:
A useful tool, to be sure! ........more, later.
Glad you found the NVIDIA Photoshop plug-in! It's super helpful and I use it all the time.
Thanks for sharing your insight!
I have been having troubles achieving good displacement results too.
There is an existing tool in Photoshop CC 2017 in Filter/3d/generate bump map or generate normal map.
Of this , the Nvidia plug in (which is windows only I think), CrazyBump and NormalMap online would any of you have a recommended tools?
Secondly is there anywhere online that can offer the best practice tutorial for creating these maps and how to implement within Visualize? I'm struggling with too many variables to teach myself and achieve the best results and after a pretty comprehensive trawl on the web I can't find much.
I'm also finding that the displacement map doesn't really do what I am expecting it to do, in some cases I get no surface deviation to speak of, sometimes it even 'explodes' a crazy spikey image passing through my model, sometimes it offsets. I have no idea why.
Any tips or pointers?