Sign in to follow this  
Guest

How do I create an _L file?

Recommended Posts

Hi folks!Can anyone tell me how to create a lightmap? I've been experimenting with greyscales and alpha channels and have been getting absolutely nowhere.Can anyone please give me some advice? Thanks a lot.:) Melvinwww.meljet.comhttp://www.meljet.com/sig.jpg

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Hi Melvin,They can be as simple as a 256X256 pixel swatch of gray RGB in the 15-75 range depending on your lightness preferences at night. The closer to black, the darker they are. Lighter shades like 75,75,75 will show a fair amount of detail at night as if there are distant lights reflecting.Once you have a RGB value you like, just copy it for as many textures as you have with a _t and give them the same name.Hope this helps.BTW, you can copy any _L texture from any downloaded aircraft as a starting point, and just rename it.Milton

Share this post


Link to post
Share on other sites

Hey Mel,Anything to help our 747 guy! The _L file is a texture with an alpha layer. It should correspond to a _T file of the same name; ie, it should have the same proportions, with the same aircraft parts in the same places. When FS renders the night model, it effectively multiplies the RGB channel (the normal, non-alpha part) of the _T file with the RGB channel of the _L file, kind of like what we had to do in Photoshop to generate _LM files for FSDS models. But here's where the alpha channel comes in: if the a/c part has lighting that is affected by the landing lights, only areas where the alpha channel is black will be used when the landing lights are off, while all areas will be used when the landing lights are on.Let me give an example to hopefully make it clearer: Let's say you have a fuselage section, and it has windows and an area where you'll want a landing light splash. You paint up Fuse1_t.bmp, and now you're working on Fuse1_l.bmp. In your standard RGB channel, start with everything black. Now make your windows: if you make them white, they will show up exactly like your daytime windows; make them yellow to get a yellowed version of the daytime windows, darken them if you want, etc. Now make your landing light splash: it should be just a splash of white (or yellowish or bluish, however you prefer) color on your black background.Now move on to the alpha channel. You want your windows to appear in most conditions, so you make sure that the alpha channel there is black. You want your landing lights to appear only under a specific condition (these conditions are defined in the model somehow; I haven't gotten to that point in my model, so I don't yet know how, but hopefully someone here can point you in the right direction if that's what you need); so where the landing lights are, make sure the alpha channel is white.The rest of the area of the alpha channel doesn't matter, with one big BUT. If you use Imagetool to convert your PSD file to DXT3 format, and you have only black and white in the alpha channel, it will save it in a bad format. You have to trick it by having a third color (gray) somewhere. So find some part of the alpha channel where the RGB channel is just plain black, and put a little gray patch in the alpha channel there. That will fool Imagetool into formatting the file correctly.And that's about the extent of my knowledge :). I'm happy to answer questions on anything I wasn't clear on.Matt

Share this post


Link to post
Share on other sites

Thanks a lot, I've just completed the light maps for the 747-400. The great thing about the _L system as opposed to the _LM system from FS2000 is that one lightmap will illuminate any livery you paint in the _T file. Whereas with the _LM system, you were actually creating a shaded version of the livery you were painting - and you had to do that for every single livery you painted.Anyway, I notice that my reflections disappear when the lights are on/lightmaps are displayed. Is this normal?Thanks again!:) Melvinwww.meljet.comhttp://www.meljet.com/sig.jpg

Share this post


Link to post
Share on other sites

Without the _L maps, at dawn/dusk/night, with lights on, the _t objects go transparent. The _L takes over with lights on for the night textures at which point, no reflectivity.This is how I see them anyhow. :-)Milton

Share this post


Link to post
Share on other sites

As a painter , i prefer the LM system , it gives you more control over the colours.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this