I previously started a topic with a similar name when I was modding MM6. Since then it has unfortunately been discontinued, and I won't continue for a while, sorry.

The reason in short is that I couldn't implement my main idea in it, which would have been the best point of the game. I'll write about it in more detail in a moment, and I try to describe it briefly and straightforward.
However, as I wrote it before, my project will not be interrupted, what will happen is that I will transfer my ideas and concepts into MM7 and design a huge modified version. A lot of things will be changed in it, txt/lua/editor etc, so the usual stuff. On top of that, several completely new maps and dungeons are planned (still are), so there will be more to do.
What I think will be the backbone of the new MM7 is the addition of new objects. You don't mean a table, a wall or a roof with no function, but new castles that can be accessed from the inside and outside, suspension bridge systems and the like.
This is where things got stuck with MM6. It's not yet possible to fully exploit the creative stuff

So, the problem and the Blender tutorial is below (anyone not interested in 3D modeling, feel free to skip this paragraph):
I'm designing new objects in Blender that not only function as "decoration", but can be run around on/into them, like in the case of Ironfist Castle (although it's not such a complex obj). When I place an object in outdoor map in MM6, I have to be very careful to erase the faces that are not visible, otherwise it will blink, glitch. Depending on the angle you look at it, you either see the face opposite or the one behind it, as if the game can't decide when to show which one. There are several solutions to remove the unnecessary geometry, I describe one here, and here's my little comics for it:

- So in BLENDER: Edit -> preferences -> Add-ons tab, find and turn on "object: Boolean Tool"
- 1. You have two objects, a cube and a hollow tube. The colors show the orientation of the faces (normals), blue is the visible/not traversable side of it, red is the invisible, traversable side (so it's like a 2D wall section has only 1 side).
- 2. You want to merge the two bodies, drag them into each other, but the sides stay the same as the inside, MM6 will get pretty stupid from it.
- 3. You select one of the bodies in object mode, add "Boolean modifier" in the "Modifier Properties", then check "Union" and specify in the object which body you want to merge it with. By the way, the guy they named these operations after was called Boolean, probably because he really liked modifying, or I don't know

- 4. You still have to delete your original object, and with the new one the internal geometry will disappear nicely, the cube will be traversable/transparent, MM6 is happy
- The only problem is that this is still only half a success, your mischievous object still has a bottom.. This can still glitch from the outside when viewed from certain angles, so MM6 is actually only partially happy, I just lied before XD. A much better solution is to design your object from the start with removing continously the unnecessary wall parts. If you already have, say, 6000 faces, and you have to pay attention to their orientation (red or blue on the left side of that chest, or the top of the column you can only see on the fly anyway), your hair will fall out by the time everything is in place.
- 5. Then there's the problem that if there's no internal geometry, how are you going to run through the corridor to cut that goblin??
The problem is that even if you've made that object, you can't use it by walking around in it. If, for example, you reach a 90° turn in a tunnel (we are still in the outdoor map), the wall behind the turn will glitches through the wall of the corridor that is covering it at that angle.
This is where MM7 and Hardware Accelerated 3D come into play. The support solves this problem, if two (or more) faces slide into each other, you will only see the upper one, from all angles (you have to make sure that if there are 2 on exactly one axis, i.e. on the same coordinate, MM7 doesn't tolerate it that much either).
At this point, I transferred my items/ideas from MM6 to 7 and working on modding it right now. I'm just improving Deyja with bridges and stairs, according to Blender there are at 3106 faces and 7298 edges, and I'm not at the end yet, but I think the end result will be pretty good.
So much for Blender (thanks to Grayface for the guide!).
And the interesting part. I'm mostly done with the starter island and Harmondale renovations, I'll link those below. I plan to transform all maps in roughly the same style and make them more interesting. And after that comes the even bigger work, with completely new locations and cities, each with a separate story and side quests. That's why I say, it won't be ready soon, but my enthusiasm is unbroken.

Harmondale has been given a wall to protect the city, and there will be someone to defend it against!

The goblins got a real castle instead of flat little piles of stones, from which they can raid as they please.

Emerald Isle has grown to have almost the same walkable area as the starting island. The theme will be pirate and treasure heist. As a dungeon, there are two new ships on the map, which can be looted, as well as the pirates' treasury cave. The pirates will be quite strong, but it will be possible to sail back to the Emerald Isle at any time, probably from the Tularean Forest.

I welcome ideas and comments about anything. I would also like to add that I still don't know a lot of stuffs and mechanism (especially scripting), I'm probably doing a lot of things wrong, but I'm trying to improve myself.