# Mapmaking Discussion & Philosophy (WIP/Critique) > Software Discussion >  Notch (creator of Minecraft) has started explaining his Procedural map generation

## guyanonymous

http://notch.tumblr.com/post/3746989...eration-part-1

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## Redrobes

Cool Thanks, that made my day. He is talking about the large scale mapping problems and how there are errors due to the lack of accuracy of OpenGL and the limitations of 32bit int for the block positions. These are things that I specifically designed my game engine to avoid so its real cool to see that he is well behind the curve on that one. When I place a map down on my ViewingDale on another planet on a piece of land and the icon is small - like say a chair in a room, it should have the same positional accuracy as one placed in a room on the original planet a long way away. If he cant do this then he is going to be in a world of pain when it comes to people playing in large areas since his engine is going to wibble and jitter all the positions and this is what he is saying that happens - it gets more buggy as you go out. I kinda feel for something that is so popular, thats pretty lame. You cant rely on the float implementation of OpenGL at such extreme values. He is going to have to completely redesign his whole engine to cope with that if he wants to make very large scale buildings. Very interesting that - probably just to me but interesting all the same.

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## guyanonymous

Well, to be fair, the tallest a building in the game can be is 128 blocks, including the bottom bedrock layer.

And for people to move far enough for these issues to effect them involves modding/cheating, and, realistically, isn't something that 99.99999% of users would encounter during normal game-play.  

Here's some user video of what happens etc.. http://www.minecraftforum.net/viewto...p?f=35&t=53577

And here's some info: "At 12,550,820 units, the normal world stops and these edgelands start. They continue until 32,000,000 units, where they suddenly stop and nothing is beyond them."

Each unit is ~1m in real-world terms, so the issues don't start until people have gone 12 550.820 km in any direction from the center of the world (the spawn point), and they can continue (albeit with distortions, slowdowns, etc) until they've gone 32,000 km from spawn.  

I think he's doing OK.

That said - I'm all about endless worlds etc, and planning ahead.  Imagine how much resolution we'd have if each block was 1dm instead of 1m (we'd need a bit more height in the world)...or 1cm.  Let's get some 64bit goodness rolling in games and other applications people!  :Very Happy:

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## Redrobes

Yeah I guess what he is doing is not exactly world building with lego is it. One of the things I needed in mine but I would have also thought would have been good in his too tho is where you can tie up two peoples creations in blocks together and make the hierarchy. So that by adding more and more peoples creations you from a collection of buildings to a town and then many towns to a world. So once he is heading down that road he will encounter the same kinds of problems.

If you want blocks of 1cm then you might as well go for a height map. Ok so he can do holes and caves but man, have you seen the memory footprint for 3D solid block models ??? Obviously adding one more dimension really multiplies it. I am not at all surprised he has a 128 block limit going skyward.

In the near future I am going to be posting something quite relevant to real time world building so keep your eye out for it - probably on my blog I expect.

NINJA: Ahh - looks like Monks has beaten me to it...
http://www.cartographersguild.com/sh...l=1#post147148

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## monks

HAAAA! ...oops...:-D 
 Interesting thread  :Wink:

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## monks

Just caught a few videos of this. What a novel idea! I especially like the caves. If only it was 64 bit. I think given a few tools for editing, it could go somewhere really interesting.

monks

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## monks

For an alternative view on things: http://dev.codeflow.org/entries/2010...s-in-opengl-4/

monks

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