So I decided to dig into Generic City to see if I could get the file size down. When I made the meshes I used any old texture format that I found with no thought or care (.jpg .tga .png). That was a big mistake I know. So I spent 2 days opening every texture in Paint.net and converted each one to the .dds format, observing the compression type in the wiki https://wiki.beamng.com/Exporting_Textures_-_DDS_Files The good news is the file size of the map has shrunk a lot! Now for the problem. I thought I would just have to change the file extension in the materials.cs from .jpg .png or .tga to .dds and job would be done. Sadly this resulted in a bunch of broken materials with the dreaded orange NO MATERIAL texture scattered everywhere. Some of the materials worked but a large majority got broken for some reason. I'm not sure of the best way to sort this out. If I open a model in the shape editor and pick a broken material and edit it to point at the correct file it remains just a blank white preview icon and wont show the texture. Any clues on the easiest way to swap the materials to a new format?
