From Valve Developer Community
Proper execution of this program included:
- Creating a targa (.tga) image with _height appended before the extension.
- Creating a text (.txt) file with _normal appended before the extension, containing the following:
Keep in mind:
- You could change the bumpscale if you didn't like the output you were getting.
- The targa (.tga) image and text (.txt) file should have the same name without their appended text and extension.
Height2normal should be executed with the text file name.
ex: height2normal "C:\a\b\c\tgafile_normal.txt"
The output created by running height2normal will be a targa (.tga) image.