Materials, Part 2. Seamless Textures and How They Are Used
(version September 16, 2007)
The subject of materials is extremely important to all aspects of 3D, especially in creating models and in animating scenes. One subchapter of materials is SEAMLESS TEXTURES. They come in handy in many areas. In this short article we focus on some areas of their use. We'll take a look at collections of seamless textures available at the 3D Animation Lab, and we will look at tools for creating seamless textures. There are many, so we can only do a survey of the major kinds. We'll introduce a method using Photoshop (or Artweaver) for turning any texture into a seamless texture. This knowledge and some practice with seamless textures will make you an expert modeler and animator.
What makes a Texture Seamless?
Let's start of off by looking at some seamless textures from the collections in the 3D Animation Lab. We'll take a look at the ones from Marlin Studios (Arlington, Texas). [By the way, Tom Marlin is very interested in our 3D Animation Lab. We have spoken with him and written to him, and try to keep him posted on our efforts. We got very favorable licensing from Marlin Studios for the Super Krypton Pack of textures and models, and this helps support the 3D Animation Lab so that we can provide you with state-of-the-art technology.] We have below two seamless textures from Volume 10, Rooftop Materials (Seamless Textures), Shingles.
We'll assume that we are modeling a building and we will use one of these for the roof. SEAMLESS means that I can lay down successive copies of the image to the right or the left, to the top or the bottom, and the images will fit together perfectly without showing a line at the edges that come together. If I am working with a small seamless image, I can use it repeatedly to cover a wall or a roof in my building, and it will fit together without leaving lines where the image files came together. Here is an example of what we mean below.
In the above example (done in Photoshop) five copies of the original seamless texture file are used, one in the middle, one to the left, one to the right, one on top, and one on the bottom. It all looks like one continuous image, flowing with lines showing where the edges of the different copies come together. If I scale the original seamless texture image larger or smaller, it should still work this way, but extreme scaling up or down may introduce some problems. In normal ranges it should work the same way. From this example you can see where a texture file that was 1024x1024 (pixels) can be used to cover surface three times as large in either direction. Seamless textures do not have to be at very high resolution in order to be used with much larger objects. Ordinary, non-seamless textures are generally needed at very high resolution to handle the largest size object you need to work with. But seamless textures can be applied again and again in a row in order to cover a large object.
(How the above image was created in Photoshop: 1. Create a new file 3000x3000 pixels, sufficiently large to hold all your copies. Photoshop will scale this down to fit your screen. 2. Open the seamless image file that you will use, Select All and Copy. 3. Click on your large, blank 3000x3000 pixel image to select it. Edit | Paste up to five copies into your new, blank image. 4. As you paste a copy, use the Selection Tool to move it to the desired location. NOTE: This is a handy procedure to use in building new images which are made up of other images. Practice this technique and get to know it well.)
You cannot do absolutely anything with textures and expect the results to come out perfect. Here is an extreme example of what we mean. In this example the entire ground was covered with the tiled shingle texture used above (see image below). Although the problem is not that we have an issue with the edges, it is simply that on a very large scale with tiling of almost any image, you will start to get unwanted patterns in the overall object. Here the ground has an unexpected pattern to it of one of the shingles looking slightly raised up. On a small scale of repeating and tiling an image you will not notice this pattern. But over very large objects, such as ground cover for the entire ground in a scene, you will hit this problem with all seamless textures. This happens because the ground here is flat. If it were a more normal outdoor area with some raised areas and some dips, it would be much less noticeable. Some of the seamless textures in our collections are of ground cover: asphalt, dirt, or grass; these can also create unwanted patterns when applied over a very large surface. The best solutions are to break the surface up in reasonable ways and apply the textures to smaller sections. A terrain with bumps and dips would have helped here. Scaling up the texture may also help some. That would be another approach to experiment with in your scene.
Still other choices are possible when working with large surfaces such as complete ground coverage, or just a large area such as a large parking lot in a scene. Seamless textures may not always be your best choice. Certainly try them out since we have an abundant collection in the 3D Animation Lab. In the long run procedural shaders may be the best choice for certain kinds of work. A separate article will talk about procedural shaders. For now, let us give a simple definition of this technique, and later we can go into more careful detail. A procedural shader works like applying a texture, but it is a function that generates the texture. Generally it can handle very small and very large scale well. In fact if your scene may be scaled to larger sizes, procedural shaders may be your best answer. In most cases SEAMLESS TEXTURES will serve you well, but you should keep in mind that there are these limitations.
The following Seamless Texture Collections from Marlin Studios are in the 3D Animation Lab.
Volume 1, Seamless General-Purpose Surfaces
Volume 2, Seamless Rustic Exterior Surfaces
Volume 3, Seamless Ultimate Interior Surfaces
Volume 4, Seamless Classical Stonework
Volume 5, Seamless Downtown Surfaces and Signs
Volume 6, Seamless Architectural Ornament
Volume 7, Seamless Great Textures of Europe
Volume 8, Seamless Absolute Metal Surfaces
Volume 9, Seamless Fabulous Fabrics
Volume 10, Seamless Rooftop Materials
Volume 11, Seamless Great Textures of the Orient
Additional Volume: Amazing Sci-Fi Textures
Using Photoshop (Artweaver) to Make Any Texture Seamless
Although this will not work well with all textures, it is possible to turn any texture into a seamless texture. For illustration purposes we'll use the following non-seamless texture.
In Photoshop (or Artweaver, where you can find the same Filter option) use the Filter | Other | Offset option and you will get a seamless image. The new edges can be blurred or blended with a brush to reduce their impact. [NOTE: The Filter | Other | Offset option is not known to many advanced Photoshop users. It does not get quoted a lot.]
First, look at the result of using the Filter | Other | Offset option. (Choose any offset that moves the center of the image away from the new center.)
When used in the group of five textures cluster as with the shingles, you get the following result with no blurring or blending of the resulting edges. This technique is not something you want to do all the time, but it may help solve a problem in a pinch.
Using Seamless Textures for Your Objects
Now that you see the significance of seamless textures and the easy way to turn any texture into a seamless one, it's time to start using them in your work. Most of the time you will "Tile" the texture map (image file), just like putting down floor tiles or carpet tiles on your floor. By changing the "Scale Factor" in your 3D application you can change the overall size of the image. For example, a scale factor of 0.333 means use 1/3 the original size whereas a scale factor of 3.000 means use 3 times the original size. The larger the scale factor, the fewer tiles it will take to cover your area. The smaller the scale factor, the more times will be needed. In a later article we will discuss UV-mapping and how that can work with textures. This will expand your knowledge of textures even further.
Seamless Texture Generator Tools
A number of seamless texture generators are available at cost, and some of them are quite excellent. We'll take a look at a free one in detail, but you may enjoy reading about some of the others. One recommended seamless texture generator that is not free is called ImageSynth from Luxology. Take a look at the Web page for ImageSynth and read the description. This is a handy tool to have and work with. It is available both as a standalone tool and as a plug-in for Adobe Photoshop.
The free tool we are going to look at is SpiralGraphics Wood Workshop. Use this link for a free download. The software includes an excellent Help File for getting started with the tool. The opening screen looks like the following (below).
After you make a selection the screen changes to the following.
Important aspect of this software these. 1. It is all free. 2. You can select Render Resolution sizes as you need, including custom sizes. 3. You can choose from Uncut Wood, Wood Boards and Wood Patterns. 4. Once you click on a wood texture, you go to a screen with additional sliders that let your customize your choice. 5. Render your choices. 6. Export the image in a variety of popular formats. You now have a seamless wood texture which you designed in the size you need. You can use this texture in your 3D applications.
Here is our resultant seamless texture that we just created.
Spiral Graphics has a couple more free tools worth knowing about. The flagship product is the Genetica seamless texture creator, which is not free. But Genetica Texture Packs can be downloaded for free. These are textures that are created using the Genetica paid tool and distributed in the GTX format. But they can be read in the free Genetica Viewer and saved in popular formats. You can size them to the size that you need up to very high resolutions. We encourage you to take a look at these free tools, download them and experiment with them. This will greatly expand your personal collection of useful textures. The Genetica materials are complex materials of many different types and produce interesting effects.
This concludes our article on Seamless Textures. Take a moment to look over the Topics for further exploration and reading on your own.
Additional articles will appear in this section.
Topics for further exploration and reading on your own
1. Work with a SEAMLESS TEXTURE form the 3D Animation Lab collection and create an example like the one with the shingles where five copies are used. Work with Adobe Photoshop, Artweaver or Project Dogwaffle. Use a texture from Marlin Studios. We have many examples of seamless textures in the Marlin Studios collections.
2. Explore each of the Marlin Studios SEAMLESS TEXTURE collections (all 12 volumes) using a picture browser, such as P3dO or Adobe Bridge (both are in the 3D Animation Lab). Get acquainted with the contents of these collections. The title does not tell you all. This will be a big help in the long run when you are working on a project, because you will remember that needed texture and be able to find it in one of these collections.
3. Explore the Adobe Filter | Other | Offset option and create your own seamless texture from a non-seamless texture. Also do this in Artweaver so that you get used to it as well.
4. Tell a friend what you learned by reading this article. Show him or her some examples. You will increase your understanding of the topics presented here when you present them to someone else. Explain to them the differences between Photoshop and Artweaver.
We enjoy hearing from you. Some of the questions listed above will appear in future "Topics in 3D" articles. Please send your comments about this article to 
