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BMR's Generic Map Tutorial Part 01

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BMR's Map Making Tutorial Part 01

Difficulty: Intermediate
  • Working knowledge of image editing software
  • How to use layer masks

So, you've got your homebrew game all up and ready to go. Players are set, dungeons are made, Evil DM Laughter™ is primed. Then, one of your players asks you, "Wait a tick, Mr. Evil DM! I, Mr. Inquisitive Player would like to ask you something. We're currently in the Dungeon of Reasonable Doom, but our base is in Generic Townburg. How far away is that from where we are?"

Now, one possible way to go about this is to just say, "And then, Mr. Inquisitive's character steps on a trap. Now roll a Reflex save against DC... oh, let's say... five billion, to escape the trap." That, however, is probably not good DM practice. You could always just give a number, but wouldn't it be so much cooler if you could whip out a map and say, "You are here." whenever your players ask? And it is exactly that which I shall be going over today!

Before we begin though, I would like to say that this is not the be-all, end-all of map making. There are many, many ways of making maps, but this tutorial will just cover how I make my maps. For my image editing software, I use the GIMP. I will, however, attempt to make this software-neutral, so I will be going over the steps and techniques, but I will not be going over specific functions, key-shortcuts, etc... as these will tie the tutorial to a single editor.

Right, with that out of the way, let's get started!

Part I: Making the Map Mask

Righto, so we'll dive right into the actual workflow. I'm going to assume that you already have some general idea as to what you want the map to look like, so we won't go into that to much. First stop, create an image in your image editor. Generally, any size will work, but something to keep in mind is that the larger you make your map, the more detail you'll be able to put into it. Conversely though, larger maps will need beefier machines to deal with, so try to strike a good balance. For this tutorial, I'm going to go with 800×800. It's a decent size for the purposes of this tutorial, and we'll be able to get an ok enough level of detail into it. For my own maps though, I tend to go crazy with sizes no lower than 3,200×3,200. But that would be silly right now.

So, you've got your image up, go ahead and fill it with a solid black. Once that's done, you'll need to fill the entire thing up with difference clouds. The settings on various platforms will be different, but you'll want something nice and detailed. Something like the image below:

Looks horrible, don't it? That's ok, we're not done yet. This is just the first step we'll need in order to get where we need to go.

The next step is to adjust the brightness and contrast of the image. Where this is located will vary depending on your software, but all image software should have an option that provides you with sliders to adjust brightness and contrast. You'll want contrast maxed all the way. With the brightness at default, and the contrast all the way up, you'll get very hard black and white blotches. Now here's the magic, adjust the brightness slider. As you do, the amount of black or white will vary. Try to strike a good balance, as the white blotches will turn into your landmass.

You should eventually wind up with something like this:

Righto! Now, however, comes the tedious part. What you're going to do now is to grab the white parts (using whatever selection method works best for you) and you'll move them around. What you want to do is overlap them until you manage to get the shape that you want. Black is water, white is land. Granted, this will take some doing, but once you get the hang of it, it shouldn't be too hard.

One thing to take note of though, is that you don't want to do too much rotating. Rotating is fine in moderation, but too much and you run the risk of messing up your nice clean lines. You could rotate with no interpolation method, but you could get jagged lines. If you will rotate, rotating by 90 degrees should be fine, but other than that you should avoid it.

What you want is a nice clean mask, like so:

As you can see, I've removed the extra bits of white. All that's left is the white land and the black water. Now, it's always good practice to rename your layers so that you know what you're working with. Name this one "mask" (or something similar) as we'll be reusing it for other layers later on.

Now, to exciting parts! Here, we'll start with creating the water. You can go with generic blue if you want, but I like to use textures that I've picked up over the years. One particularly useful pack that I've used at times is located over here. Granted, it won't have everything that you need, but with a bit of mixing and matching, you should be able to get a good enough texture for what you need to do.

For my water, I'll be using this:

One thing to keep in mind is that you should make sure that your textures are seamless. That means that you can tile them without the repeats being too blatantly obvious. How to create seamless textures (or how to create textures at all) is beyond the scope of this article though, so we won't get into that.

For this layer, we don't need to create a mask yet. That will come in later. Go ahead and rename this layer to something like "water".

The next thing is to create some land texture. Typically, you're going to want at least a green and a brown, for areas of varying levels of vegetation. We'll start out with green. I'll use this:

Use whatever texture you've got, and fill up a new layer with it. Next, create a layer mask, using the black and white image that we created earlier. How this is done will vary, once again, so do it in whatever method works for you. Typically, this can be done with a right click on your layer, leading you to whatever mask option is available.

Hopefully, by now you should have something that looks like this:

Now while that looks... ok... I guess... it's not really all that great. Remember how I said you should have some browns as well? Well I'll be using this texture:

To make coastlines.

To do that, I'll duplicate the vegetation layer (you named it, right?) and change the texture from the green to the brown. This will, however, change everything, when all you want is the coastlines. You could painstakingly draw everything, but that's tedious and who has time for that nonsense? Instead, what you're going to do is to edit the layer mask. Select all of the white (again, using whatever selection tool works for you) and shrink the selection by a few pixels. How many pixels you'll need to shrink will vary depending on how big your image is, and how wide you want the coastlines to be. For this image (800×800) I'm going to shrink the selection by a mere 5 px. You'll want to feather this selection as well, roughly 5-10 px should be good.

One thing to keep in mind, depending on your settings, your selection tool may automatically add a feather to your selection. If so, make sure to adjust accordingly.

Once you've gotten your selection, fill it up with black. That will turn that part of the layer invisible, leaving only the coastlines. So you should wind up with something like this:

You'll notice though, that your coastline has a hard edge next to the water. To fix that, you can extend your white mask a few pixels out into the water, feather it, and fill it up with white. That gives you this:

So right now, our map is looking better, but still fairly barren. In the next step, we'll work on mountains and other details. As I'm limited by the number of pictures I can have on here though, head on over to Part 02 over here!

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Updated 04-27-2018 at 01:41 PM by BMR