SIM TRAXX is a very good modding group. The only problem I have with them is they have 100 projects going at once and not one of them is "finished". Now, I don't mind if they want to work on their tracks for the rest of time, meaning they'll never be finished, but all bugs, graphical abnormalities, invisible walls, etc. should be gone from at least a couple of projects by now. It feels like they'll never get out of Beta - GMail anyone?
There are a couple of SIM TRAXX tracks that I absolutely love. If you don't have TOR POZNAŃ, TRANSFAGARASAN & PEYRE I suggest you download them immediately. Tor Poznan is actually laser scanned. Peyre scares the crap out of me and Transfagarasan is simply awesome.
Wow. I just visited their website - looks like they've added a good 5 or 6 new tracks to the list - none of them ready for Public release, of course.
I really should just toss them $20 for full access to all of their most recent builds and such...Even though I don't believe their quality is as good as some track builders, they still have provided me with countless hours of enjoyment and $20 is a fair deal.
The Road Mesh.... Okay, you know how video games 3D graphics are made up of polygons/triangles? The more polygons that have to be drawn/rendered, the slower the sim will run unless you have very beefy hardware. So, track/car modders need to keep their poly count as low as they can without sacrificing quality. It's a tricky balancing act for beginners. Well, you know what the roads look like when you're driving on them in Assetto Corsa. Let's just use Spa-Francorchamps for this example. The road isn't perfectly smooth. All tracks have little bumps or depressions here or there. Some tracks have some scary bumps in certain parts. Well, the only way to properly make those surface blemishes is to use a lot of polygons which we know will sacrifice rendering performance. So, what modders do is, they make 2 different meshes for the track surface. One is the mesh that you're going to see when you're driving on the track. The second mesh is going to be a much higher resolution (more polys) mesh that isn't visible, but it's what the car is actually driving on. Make sense? This is all a very basic description, but for the most part that's what it is.
That's what caused all that drama with Rainmaker's tracks. First, he wasn't asking the builders permission to transfer a rFactor 2 map, for example, to Assetto Corsa and that's a big no-no in the modding community. Secondly, Rainmaker refused to make a 2nd road mesh underneath the graphical road mesh...so all of his tracks looked okay, but they were kind of crappy to drive on. Dozens of people would say to him, "Dude! If you're taking the time to convert all of these tracks...Can't you spend 90 minutes making a higher resolution surface mesh?!" He would refuse. For what reason, I don't know. It kept going back and forth like that for a while until Rainmaker finally picked up his ball and went home, promising he would never play with the kids on the AC Forums playground ever again.
This was all going down right when I first bought AC in 2015, so forgive me if some of my details are a little blurry...but that's the jist of it - I think.
Schwing!! 
