Introduction to Digital Modelling and Animation in Design week 4 Textures

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1 Introduction to Digital Modelling and Animation in Design week 4 Textures Thaleia Deniozou Point Lighting The three- point lighting is a standard method used in visual media such as video, photography and 3D visual effects. By using three separate positions (3 light sources), the scene s subject can be illuminated adequately, while also controlling (or eliminating) the shading and shadows produced by direct lighting. The three light sources used are called Key, Back and Fill lights and an example scheme can be seen in the image in the right. The three- point- light set- up is a classical, very simple scheme to achieve a scene with softer lighting and widely used to illuminate 3D scenes in Blender. Our Spot Light is the main, or Key light of the scene (the one casting shadow). We also need to add two more lights to fake diffusion. The next light needed is called the Back Light. It is placed behind the scene s objects (here the 3D character). This illuminates the hidden side of our scene and allows us to separate the foreground of our picture from the background, adding an overall sense of depth. Usually the Back Light is as strong as the Key Light, if not stronger (same energy). Here we used a Spot Light with Energy of 1 (Key and Back Light). The result is already far better. Finally, the third light is the Fill Light. The Fill light's aim is to light up the shadows on the front of the scene. We will place the Fill Light exactly at the location of the camera, with energy usually lower than the Key and Back Lights. The Fill light lights visible parts of the model, which were previously in darkness with just the Key and Back lights only. As you add lights, keep an overall total even to avoid over- lighting a scene.

2 The three- point- lighting does not suggest that all shadows will be eliminated but it will help you adequately light your scene and bring up the quality of your modeling. Textures After you create a material and would like to add some kind of texture to the object (i.e. brick, carpet, wood grain, etc), you then click on the Texture button beside the Material button on the Properties Panel. After you click the New button, you have some choices in the texture buttons. First, you need to decide if you wish to use one of Blender s preloaded texture generators or provide your own image as a texture. Blender is capable of using almost any image file type whether created in a paint program or is a photographic image. JPEG images are the most common. Blender can even place a movie on an object as a material. This is a good effect if you want to add animation within your animation. REMEMBER You can t add a texture unless you ve already added a material. Material and Texture properties work together. Here's what you see in the texture panel:

3 Let s say you want to use one of Blender s built- in textures (under the Type option). Some of the widely used ones are Clouds, Stucci, Magic, Marble and Wood. These can produce some interesting effects with a little practice. When you select one, setting options will open for that effect. Each texture has different tools available to work with, but some similarities are present in most: Most of Blender s texture options deal with turbulence and noise (randomness of the pattern). The wood texture also has some features dealing with the pattern of the wood grain (bands and rings). After you place the texture, you still need to go back to the Materials Buttons to fine tune the look on your object. For an example of how to work with a texture, we will apply a wood texture to a cube. We'll start with a basic cube that has a material applied to it. Since wood is usually various shades of brown, we'll make the Diffuse color brown. We'll also take Specular Intensity down a bit. We'll now go over to the texture buttons and add a new texture. Make the texture type is Wood. In the wood texture panel you will see some different ways to represent the wood grain. Sine- Saw- Tri will give you a different stripe while Bands- Rings- Band Noise- Ring Noise will give you a different pattern. For this example, select Ring Noise. Now you have a secondary color that needs to be corrected. To fix this, scroll down through your texture panels to find the color swatch to change this from the default pink to a better color. Choose a darker brown. You can also adjust the Size (X,Y,Z) of the texture (for this example: X = 5.50, Y = 6.40 and Z = 0.30) and the Noise Basis for more effects. Feel free to experiment until the texture looks exactly as you d like. Another interesting texture to use is the Stucci, which provides interesting effects on the surface of different meshes. In the Texture Buttons, select it as you do for any of

4 the other texture generators and adjust the settings. In the Stucci panel, adjust the size to Next, go down to the Influence panel and turn on Nor (under Geometry for Normal). Adjusting the Nor slider will adjust the amount of the effect. Play with the setting to get a bumpy effect on your texture. Turning the size setting way down can also give you a grainy effect. Below are some samples of different Noise Basis patterns. Image Textures The basic texture generators offered by Blender are often handy, but not always complete. Most of the times you need to place textures like grass, brick, metal, fabric and so on into your model. Anything that can be saved as a JPEG image can be used as a texture in Blender. Most other image type files can be used as well (png, targa, TIFF, bmp). Movie files can also be placed on an object as a material. To use a JPEG as a texture, add a Material as before, go to the Texture buttons and select the Image or Movie option under Type. When you select this, here is what you see for options:

5 For an example of using images, here is a cube and sphere rendered using a brick image (jpg). You will notice that, by default, the image is mapped onto the top and stretched down the sides of the object. This is called Flat mapping. This can be adjusted in the Mapping panel, in the Texture Panel. Your other options (Cube, Tube, Sphere) are shown below: Let's say I want to use the Cube mapping, but the bricks are too large. I can control this in the Image Mapping panel under the Repeat option. This way you will affect the way the image tiles on the geometry s surface. Remember that the Material and Texture panels work together. The bricks look

6 good, but the texture may be a bit too glossy and flat. You can make adjustments to Specular in Materials (glossiness) and add a Normal (Nor) to the brick texture in the Texture panel under the Influence panel. This will simulate depth and add a nice effect to the brick. UV Unwrap Unwrapping is a more precise technique of mapping a texture on an object and helps you use other features as well, like Texture paint and Baking. In order to get the UV coordinates for a mesh we must unwrap it using the UV/Image Editor. First of all we need to create the proper workspace to project our mesh upon. Split the screen in two and change the second screen to the UV/Image Editor (from the Edit Type button on the bottom of the 3D view header). Select the object (here the cube) > go to Edit mode (tab) > A > U This will bring up the unwrap menu. The Unwrap Calculations we mostly use are either the Unwrap that performs the operation automatically in the best possible way (use this for simple geometry) or the Unwrap (smart projections) that attempts to flatten the mesh and performs a mark seams operation automatically. Hit Unwrap and see how the Cube s faces unwrap in the image editor. The one is on top of the other, which is not very useful if you want to project different parts of the image in different areas of the mesh.

7 To fix this we will use the Mark Seams techniques to indicate to Blender how to Unwrap the Cube with detail. This way we will attempt to flatten the 3D shape to a 2D image using the seams as markers. So let s start over. Add a new cube to the scene and select it > Edit mode (tab). Now we will mark the seams. Which seams we select will depend on how we want to unwrap the mesh. Select them with the Edge select tool > ctrl+e> mark seam> then hit A to select everything again>u> unwrap. So you can see, we now unwrapped the mesh as a 2D image projection of all the faces of the Cube:

8 *you can use Ctrl + E > clear seams to deselect the seams you previously marked. **the unwrap object on the UV/Image Editor (2D projection) can still be manipulated as all other meshes in Blender, by its vertices, edges and, faces using the panel on the bottom header: Now that we have our cube selected let s apply a texture on the cube. The first thing to do is bring an image in. Go to Image > Open (on UV/Image Editor header) and search for your file. Once you bring the image in it will be quite big so you ll need to zoom out a bit. You may also need to rotate you image according to what it is you want to do In the example below the image has been rotated along the x axis, 270 degrees: Each of the little sections representing the unwrapped faces of the cube is called an island. We can use the selection modes as we have seen before to make the islands bigger and fit the parts of the image we want in each of them. This way we define in detail the parts of the image that will be projected on each face of the cube. For this example use the face and edge select modes to make the islands bigger. Then go back to the 3D viewport and change the shading to textured to see how the texture maps on the mesh:

9 Although you now have your texture on the cube and you can see it in the 3D viewport, if you try to render out an image you will notice that the texture is not visible. There are a couple of controls we need to do to make sure we see the texture in the render. First make sure the cube has a material applied form the Materials Panel. Then go to the Textures Panel in the Properties and select the Type > Image or Movie. Then go to Open and re- select the same image as the one you used for the UV and finally go to Mapping and select UV as the Coordinates, to instruct Blender to use the UV unwrap when rendering. Finally, trying to render again you should see the correct texture on the cube: