Hello there!
I felt like introducing myself so you can skip this part to the actual topic question.

First I want to thank both Acknex and Atari for releasing such a powerful factory to create 3D games. Thanks go as natural to you - this community which sustains the game development - I couldn't just read the manual and make the games.
Gamestudio is so much more powerful and customizable than what I'd been working with so far...
So, I said that before attempting on making a simple game I should study thoroughly and thus I kept reading the manual and the other official tutorials available at the download section, for the last couple of weeks and still hasn't finished. printed and written dozens of pages to serve as guides.

You know the car level? I want to know how the terrain had the texture mapped. I opened the level in WED, found the plane01_hmp_1216 and I saw in MED that it has 2 skins. I returned in WED and as my intuition dictated, I looked for an action of the terrain that called a multitexture shader and I found this "ffp_terr_detail" action. IIRC if the terrain has only 2 skins, the terrain is automatically rendered with the second one being for details (tiled?). But what about the action? I can't find it defined anywhere, not in any included script. So 2 questions arise:
1. Does a level need a specific function/action to render two-textured terrain?
2. What's with this ffp_terr_detail()?

Thanks for the time.

Welcome to the forum. I think the ffp_terr_detail action is not needed, you can remove it. It probably was from a time when terrain detail textures were not automatically supported and you needed such a function.

It the same with many shaders you find on the Wiki, terrain_multitexture, bumpmapping, waving grass and so on, they are all not needed anymore and are from a time when this was not yet included in Gamestudio.

Thank you.