SteelcladBeowulf Posted September 20, 2019 Share Posted September 20, 2019 Now, for a variety of reasons, I'm not interested in using Photoshop just for texture maps. I have used it, mind you, it's just that Adobe has its own problems that I can't really deal with. GIMP is a close second, but admittedly I'm still trying to figure out its own quirks, with difficulty in particular to normalmaps. As well as BC7 compressed textures, but that's an issue outside of my control. Recently, I've discovered that the alpha channel for a normal map is what holds its specular information, meaning it controls how shiny a particular part of a texture is, like the individual Specular Texture Maps. However, I'm absolutely stumped with how to use GIMP's Colour Channels to begin with, considering that it displays them differently to photoshop. Assuming that I'm not going to use Photoshop in the near future, how can I edit "only" the alpha channel in GIMP, or at least copy and paste the specular map into the normal map's alpha channel? I ask because I haven't found anything on the internet that covers it. Apparently it's not that common of a topic, nor is using GIMP for texture maps for that matter, probably because Photoshop is still that much better. Link to comment Share on other sites More sharing options...
thumbincubation Posted September 21, 2019 Share Posted September 21, 2019 I'm afraid I don't know that either. I generally just make a combined normal/specular map and be done with it. If you're not using extremely detailed textures, that might prove easier for you. Here's the guide I used to learn it. Prior to that, I was doing the thing where you remove the alpha, make a normal, replace the alpha then erase it with a 70-90% opacity eraser. Effective, but not as good as this method, I don't think. Link to comment Share on other sites More sharing options...
SteelcladBeowulf Posted September 21, 2019 Author Share Posted September 21, 2019 Huh. That video is actually exactly what I need. Thank you! Link to comment Share on other sites More sharing options...
thumbincubation Posted September 21, 2019 Share Posted September 21, 2019 Glad to hear it. You're very welcome. Good luck. Also, that thing he mentions about cutting out certain portions of armor, to make them shinier or more dull than the rest, works with the normal portion of the map as well. If you're doing something heavily embossed, like chainmail or the studs on Imperial armor skirts, you may need to select and give them a different scale than the rest of the map. Link to comment Share on other sites More sharing options...
SteelcladBeowulf Posted September 23, 2019 Author Share Posted September 23, 2019 So, I found another way to edit the alpha channel for a normal map on GIMP, just by toying around with it. All that needs to be done, is to first decompose the image in RGBA color model, emphasis on the "A" so that all the channels can go into different layers, Alpha Channel included. Once the wanted edits are made, you can just recompose it back again, also in an RGBA model. Just thought I'd share this info, if it wasn't readily available already. You can also make the alpha channel as a seperate specular map, if you want a cubemap reflection. Though you will likely need to edit that further, especially for non-metallic parts of an object, considering that it affects reflection, rather than how light interacts with an object. Link to comment Share on other sites More sharing options...
thumbincubation Posted September 23, 2019 Share Posted September 23, 2019 Very much appreciated. I didn't know any of that. I think it will help me with some retextures I've been wanting to do. Link to comment Share on other sites More sharing options...
Recommended Posts