Normal Map - Process

[Vraciu]

Is a normal map itself just a single layer "purple" equivalent to a grayscale image?   Do I have to convert it from something else?  Can I edit a file using the same colors manually?

For example, can I take the default Normal map and edit portions of it then save it or do I need to convert it again?

By my thinking I should be able to change it directly within the file itself.   Am I missing something?

[Skuzzy]

You can alter it directly.  It is just tricky to do.

[Greebo]

The normal map is not a purple-coloured version of the bump map. The bump map shows the vertical dimension in 256 shades of grey, with white being highest and black lowest. The normal map shows both height and angle to the horizontal as a 3D image with in this case a light source coming from above and to the right. It is not practical to try and edit a normal map by hand, you have to edit the bump map and convert it using the appropriate software.

[Vraciu]

Both answers above were what I needed.

Thanks guys.