Hello, to get the solution you have only to do a lot of tests and error until you get the solution, I'll explain what I did so that you save a lot of days, even months that I get to solve it, there are many terms And definitions that I have never finished understanding well for my language stick so I just go try to get it fixed, there are many who do authentic wonders with the terrain and materials and sure there is a more professional way to do it and with Best result.
I tell you what I did and it worked, in case some of this saves you time.
1- Since I had never done any of this, I did not know where to begin, so to have a ground to tread and not fall to infinity for all eternity, what I did was to open the map of the black forest, select only the ground , I gave him to copy, as I did not complain, I opened my map and gave him to paste, miraculously appeared a huge piece of land, by passing the mouse over with the tool open field and playing with the section select copy and cut I saw that I could delete some sections and reduce the terrain a bit, I started to cut like crazy, I passed and at the time I realized that I was missing a piece, it was when I managed to find out how to copy a section and paste it, but it always came out In black the piece added, so pull the ground and start again.
With this I want to tell you that if you can not select the terrain by sections and delete what is wrong, make a copy of what you have to work with it, save what you have, delete your current terrain, copy the black forest and adjust it To your needs of size and shape.
2- Once everything was adjusted, with all the materials by default, I had the happy idea to change the texture of the terrain, wanted to put sand in an area, being a beach was not well the forest floor and was when all the pain started Head, at the beginning in the editor everything had a very good aspect, to dissimulate the drawing that makes the material if it is seen from a distance, but of course that in the editor, compile it load in the game and also looked perfect, so I decided to upload it as a beta, mount a server on my pc and try it with friends, I almost had a heart attack, the floor had more blue and white checkered areas than areas with textures.
This happens because in your published and unpublished folders you save the textures you do locally and whether or not they work, your map loaded on your computer will look good, which is why I explained earlier how to do it to be sure That what you see in local will be what you see on a server.
After this and after spending a lot of time, searching and asking, in a thread of this forum, talking with Domingo, we were told that at the moment the land did not admit personalized materials, but the best thing was that my materials existed in the sdk And had those problems, the Sunday map is completely personalized "let's die of something" after all the work.
I only with my more limited knowledge could do is to change the textures that have that default terrain for something that would give more realism to my map.
In the previous answer I put what you have to find and edit if you want to change some texture and paint the floor a little different as it is by default, it is a bit lousy to clarify when you edit but if you want to look at my map what I did And compare with the original, so you can see faster than modify.
3- Finally after all this royo, which I hope will serve for you or someone who passes this and do not know where to start, is left to select the piece that gives problems, delete it, the section closest to this Well the copies and the paste where you deleted in it is bad, you will have a nice black rectangle, so you only need to paint it so that it is in line with the rest, in the field tool, you have to load your material, if Create it and then edit it and put the textures, RockMax, in another thread has put you like loading your textures.