Tiling Textures | Geometric Patterns in Tiling Textures


Geometric Patterns in Tiling Textures

So far in this course, we've dealt exclusively with organic textures that have irregular patterns. What happens when we create textures for a man-made object, such as a brick wall?
Geometric patterns present some different challenges.
Such textures are challenging because a geometric pattern must be created. Any pattern present in the source image must be preserved in the tiling. Bricks are usually laid in some specific pattern by the brick layers, and you will want that pattern to be present, and consistent, in your texture when it is tiled.

As you'll discover, conspicuous detail can cause problems with geometric textures. In this lecture you will learn to deal effectively with these issues.

In this lecture, you can expect to:

Explore the challenges of creating a tiling texture with a geometric pattern.
Learn tips for shooting source images of geometric patterns and correcting unwanted perspective issues.
Learn techniques for preparing a geometric tiling texture, correcting problems with perspective and conspicuous detail.







Man-made surfaces like walls, fabrics, and floors are often characterized by geometric patterns with repeating shapes and colors.

















Geometric patterns tend to highlight any perspective issues.










Use the Distort transformation in Photoshop to correct any perspective problems in source images.





















Check your reference images to make sure the scale of your textures is accurate.













































Pay special attention to the edges of your textures. That's where issues may arise when tiling.


































































Keep your original source image handy to help with any corrections or adjustments.

















































Set the layer opacity to guide your alignment of tile edges.










Conspicuous detail can be a problem with geometric patterns too. Ask yourself what if anything draws the eye.


Geometric Patterns


The Signs of Human Manufacture

Think of any man-made object in the world around you, and try to visualize what makes it distinctive.

Chances are, you thought about the pattern made by a human manufacturer. Our environment is made of distinctive man-made patterns: the shingles on roofs, the links of wire fences, the interlocking shapes of bricks and stones in walls, a series of lights down a hallway. The great things about humans is that we like to put things in order, whether we are building pyramids or laying carpets in abandoned warehouses.

Geometric patterns are a great opportunity for the texture artist because they represent such an obvious and natural application for texture tiling. Picking up what's truly characteristic about a geometric pattern and repeating it can create a whole world of texture information.

This screenshot from Crysis 2 shows various surfaces made up of geometric patterns: the brick walls around the potted trees, the stone columns, and the wood planks beneath the player.

At the same time, the tiling effect can just as easily be ruined by conspicuous detail. So in this lecture, we'll explore how to create texture tiles for a brick wall. This will provide a foundation for geometric textures you'll create in the exercise.

Let's begin with some insights into working with this type of source material.

Working with Geometric Source Images
Shooting Your Own Source

As we discussed in Lecture One, on a professional job you may find yourself working with stock source images—depending on the culture, art style, budget, and so on, at the game studio.

In this class, I'd encourage you to work with some photographic source material of your own. Here are some thoughts on getting together your source images.

The Perspective Issue

As far as possible, a texture image should be "flat," exhibiting no apparent perspective, like a decal applied to a model plane.

With any photograph taken in the real world, however, some perspective may be visible—and especially so with photos of geometric patterns, which tend to reveal perspective. As much as you may try to make sure the image plane is parallel to the plane of the wall when you're shooting texture source with your digital camera, there will simply be times when you can't get the shot you want.

Sometimes you will have to stand at an angle, shooting slightly from the side when you prefer to shoot from directly in front of the wall. More often, you will need to shoot at an upward angle when taking photos of a building. This was the case when I shot the image below. You can still get what you need from an image like this, but you will need to first correct for the perspective, removing it from the image.

Perspective Correction

As always, you may need to work with different parts of this image, so you should do any color correction before you start. Likewise, if you perspective correct the entire image, and save it, you can use it later without repeating this effort.

Distort (Edit > Transform > Distort) is an incredibly handy tool for fixing perspective problems. The Distort transformation provides a handle for each corner, and you can move these handles separately to alter the image. By moving the handles for the top two corners apart, as shown below, we can correct for the fact that the brick pattern is receding into the distance, toward some unseen vanishing point. Use the sides of the image as reference, and line up the vertical mortar lines so that they actually become vertical in the image.

The above image is shot in such a way that the horizontal mortar lines are very straight. However it may prove necessary to make minor adjustments as we work with the texture.

Don't Forget Scale!

As you are shooting source imagery, don't forget to think about about scale. The image below shows you what a 512x512 chunk of our source image looks like on our geometry.

My very unscientific survey of one doorway on one building (hey, it's the building I shot the brick from, so this isn't total guesswork!) indicates that a doorway is about 28 bricks in height. Our sample doorway has extra fancy stuff on top, and a little space above that, so as you can see that in the image above my scale is way off.

Given the scale of our geometry, a single brick tiling texture should be about 42 bricks high. (Remember, the scale will not be the same in all games).

The sample of 42 bricks is a large chunk of our source image, and a lot to work with. For the sake of being able to making this a more useful lecture, let's work with 1/4 that many bricks, and plan to combine four of our textures, tiled 2x2, into one texture for our "game."

Creating a Geometric Tiling Texture
Planning Ahead: Preserving the Pattern

For this part of the lecture use the source image "brick.jpg" found in your course downloads.

The image below shows a 1024x1024 selection over the source image.

Click the image above to get a closer look.

Now is a good time to start to plan ahead for some of the other concerns that arise when working with textures that have geometric patterns. If we look closely at the selection above, we can see that I've tried to place the top edge so that it just includes a horizontal line of mortar. I've lined up the left edge of the selection as best I could with the vertical lines of mortar. I was careful to include the mortar.

The left edge starts with a half brick. The right edge of the texture will need to end with a whole brick to preserve the alternating pattern, and the right edge should not include mortar, since that is present on the left side of the texture.

The bottom edge of the selection very conveniently stops at the edge of the brick, and does not include the mortar, which is present at the top of the selection (we wouldn't want two lines of mortar in a row when this texture is tiled).

Unfortunately, the bricks also alternate between half and full bricks vertically, and we now have a half brick on both the top and bottom of the selection. A quick check of the results shows quite clearly the way in which this will disrupt the pattern of the brick.

One option is to select an extra row at the bottom. This will mean that our selection will be larger than 1024. We'll have to resize to 1024 to end up with a square texture, which will result in the bricks being slightly compressed vertically. We could also select slightly less at the bottom, which would result in the bricks being slightly stretched after we resize to 1024. Fortunately, with a difference of one brick in about 21, the change won't be at all obvious.

In the image below you can see that I've deselected a portion of my previous selection, on both the bottom and right edges. Notice how it preserves the brick pattern. Of course, we'll still need to do some work to make it tile seamlessly.

Click the image above to get a closer look.

Below is our brick texture tiled in Photoshop. We're very close here to having seamless tiling!

Perspective Correction and Tiling

The biggest problem with the tiling is shown below and circled in blue. We did our best to insure that the horizontal lines were truly horizontal, but a little further adjustment is necessary.

A slight adjustment using Distort may be enough to fix our problem. To work on the texture, first select one tile, and copy and paste it into a new layer. This way we can see the changes relative to the background layer with our unaltered texture.

There is a handle in the middle of the right edge of the Distort bounding box that allows you to move both of the right corners at once. Holding down the Shift key while you move will assure that you only move in one axis, in this case the vertical. By lifting the right edge of the texture up very slightly, we can make the horizontal mortar lines match up a little better. See the image below.

We've lifted the right edge of the current layer away from the bottom of the tile, but the brick in the layer behind should work to fill that space. Flatten the image to combine the layers. To see some more perspective correction in action before continuing on with your brick pattern, watch the following video tutorial:

Select only the tile that has been altered, and tile that new texture 3x3 to see how it tiles now.

The last step can be an improvement, but we'll still have a seam to deal with. So, we move it into the center of the texture as shown below.

We can choose a portion of the original source image to paste over our latest texture, to cover the seam. If we take that approach, remember that we resized the brick we took from the source image. Or, we can use the previous version of the texture, before the seam was moved to the middle.

Setting the layer opacity, as shown below, allows us to make sure the brick pattern on the top layer lines up with the bricks on the bottom layer. Then it is a simple matter to erase the left and right edges of the texture, to expose the edges that already tile on the bottom layer.

Again, we should proceed carefully as we erase, and make sure the texture looks as good as it can.

As you can see below, our texture is looking pretty good tiled in Photoshop. It is time to test it in 3D.

Conspicuous Detail in Patterned Textures

Textures like our brick texture have a very strong pattern of their own, and this can make it less likely that any particular detail will stand out enough to draw attention to the fact that we're looking at a tiled texture. Our current brick texture looks pretty good in the 3D view shown below. Yet, there are still a couple of things that could be improved.

Different 3D systems cope differently with the display of textures in 3D. In the image above, the bricks toward the right look somewhat different from the bricks on the left. This is due to the way the texture is reduced in pixel dimensions for display in 3D—or to put it more simply, the bricks on the right look different as a result of being further from the camera.

At the top of the texture there is an area of what looks like slightly dirty, or perhaps just slightly darker brick, and when tiled, this creates a horizontal line of such brick that is somewhat noticeable (indicated by the red arrow in the image above). If we look closely at the texture we see that in fact the darker brick occupies more of the texture, and the solution may be to change the lighter areas rather than the darker.

There is one brick that stands out a bit, circled in red. This brick is half black and half red. It is a simple enough matter to cut and paste over it a less conspicuous brick from elsewhere in the texture.

The process of reducing the appearance of tiling is really the same as that used in the previous lecture, so I won't take you through that process again for our brick texture.

Common patterns in textures include various types of brick, block, and stone, and wooden structures such as those constructed from planks. Most often patterns of the type discussed in this lecture occur in man-made materials, but nature does provide some surfaces with geometric patterns as well.

Learn about the ingredients of a good texture set.
Explore the pros and cons of using variation textures in a set.
Learn about the different types of textures in a texture set.
Learn about the importance of end grain and transitional textures.

Apply the techniques you've learned to make your own tiling textures of a geometric nature.

Share your thoughts on the challenges and approaches to making tiling textures with geometric patterns.