2.1 The Ground
With a canvas in place and a grid overlaid, we can now start creating layers for our various map features. Beneath them all, we need the ground - plain dirt.
The technique is the same as creating the grid. We need a dirt texture - one that tiles neatly and seamlessly - out of which we can create a fill pattern. Google Image Search is your friend here but you need to make sure you have the owner's permission to use the one you find. There are plenty of good seamless textures which allow you to use them for personal use free of charge.
Once you have your texture, follow these steps...
- Load the texture file into Photoshop.
- Reduce the image size to one inch by one inch, at whatever DPI you are using for your map.
- Create a pattern out of the inch-square piece of dirt, just as you did with the grid.
- Go to your main map canvass, create a new layer called "Ground" and fill it with the new pattern, again as you did with the grid.
You may find the texture works better at a slightly different scale - say, for example, shrinking it to 2 inches before you define it as a pattern. You can also adjust the colours in Photoshop to get a look you are happy with.
Creating a grass layer is done the same way with a few additional steps. The grass, unlike the dirt, is no mere background. We need to be able to paint grass with the Photoshop brushes and create shapes and areas as needed. However, the first steps are the same as for the dirt: Find a grass texture, create a pattern and fill a layer as you did with the ground. Call the layer "Grass". It should, of course, go atop the ground. For now, it will cover it completely.
Next you have to create a layer mask. This is the trick that allows us to "paint" with grass. Make sure you have the grass layer selected and click the layer mask button at the bottom of the layer palette.
Once you've done so, your grass layer should look like this.
On the left, you have the layer thumbnail, as normal. On the right is the layer mask. You can select and draw on either one by clicking the thumbnail.
If you're unfamiliar with layer masks, they determine what parts of a layer will be displayed. If you draw on the layer mask in white, it will reveal the grass where you draw. If you draw on the mask in black, it will hide it. By using black and white pens, we can now draw with grass. The handy thing is that you're never actually changing the grass layer so you can draw and erase over and over again without losing the grass texture itself.
However, it is easy to forget, accidentally click on the grass layer (rather than the mask) and start scribbling. To prevent that, we can lock the grass layer. To do so, select it by clicking on the left most thumbnail and click the "Lock Image Pixels" button above the layers.
Once locked, we can no longer draw on the grass layer (although we can still select it) and it will protect us from mistakes as we create maps. When you're drawing with grass, you should instead be working on the layer mask.
2.3 Drawing With Grass
Much of the time, you probably want to fill the screen with grass and then erase it back to dirt to create clearings, paths and so on. Whether you're drawing with grass or erasing it, I recommend using the maple leaf brush, which you can find near the bottom of the list of default Photoshop brushes.
The brush produces a tatty, natural look, making the grass appear more realistic.