May 2009

Adding Ambient Occlusing as a lens effect

Adding AO globally
While you commonly would setup and render the ambient occlusion in a separate pass, it doesn’t mean it can’t be done in a single pass as well. By adding the AO to the camera rather than the individual materials, you can control the effect globally and you don’t have to change a single material. Open the scene cube.scn from this issues DVD. Press [8] to open an Explorer, select the Camera and press [7] to open a Render Tree.

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Animating frost growing across the surface

This is a very common question. Okay perhaps not the frosted effect, but the part about changing the textures or materials for an object over time. You obviously need a surface for the material so start a new scene and create a simple object. Or just open the scene frost.scn from this issues DVD. Select the frost object and from the Get > Material menu choose Phong and Press [7] to open a Render Tree. Get a Gradient node from the Nodes > Texture menu and a Mix 2 Colors node from the Nodes > Mixers menu. Connect the gradient node to the Weight input of the Mix_2colors node and the Mix_2colors node to the surface input of the Material node. Double click on the gradient node to open the PPG and switch to the Texture tab. Click the New button and from the menu choose Planar XY.

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Rendering XXL Sized images

While the images for a typical brochure often are printed at a resolution of between 150 and 300 dots per inch (dpi) posters rarely exceeds 100dpi. Once you reach the size of billboards you’ll probably end up at a resolution less than 30dpi. With the above in mind you should have limit the need for extreme high resolution rendering, but there are situations when you do want the extra pixels. The central problem with large images is the amount of RAM needed. Not only do you need to cover the frame buffer/image itself which can easily grow to several hundred mega bytes (this is without considering the recourses need to actual compute the rendering) you also need to have this amount of free continuous memory.

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Coloring hair using procedural textures

Creating the procedural
Select the pelt object and press [7] to open a Render Tree. Get a Fractal node (from the Nodes > Texture) and a Color Matte node (from the Nodes > Color Channels). Connect the Fractal node to the Input of the Color Matte node and the Color Matte node to the Ambient and Diffuse input of the Blinn node. Open the Fractal PPG. In the Texture tab, click the New button and choose Planar XZ. Switch to the Advanced tab and set the UV Remap Maximum to 5 for all three axis.

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Animating a mechanic billboard in Softimage XSI

Start by opening the Billboard.scn scene from this issues CD. The scene contains a bunch of trilons or triangular prisms, 300 to be precise. Using a couple of thousands would obviously be more striking but for the sake of demonstration the number is keep low. While any of the prisms could be used to animate their rotation, it’s a good idea to separate the animation parameters from the actual billboard. Start by selecting the null object named Prisms_Rotation. Press [C] to activate the rotation tool and press [K] to set a keyframe at frame 1. Go to frame 16, rotate the Prisms_Rotation 120 degrees on the Y-axis and set a new keyframe. With the rotation still at 120, set another keyframe at frame 80. Press [0] (zero) to open the Animation Editor and select the function curve for the Y rotation (roty). From the Curves menu choose relative Cycle. To change the pace of your mechanic billboard, just move one of the 3 keyframes.

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Create procedural leather material in XSI

Color variation
Start by installing the BA Shader Collection Essential add-on from http://www.binaryalchemy.de/index_dev.htm. Open the scene leather.scn from this issues CD. Press [8] to open an Explorer and select the group Leather_material. From the Get > Material menu choose Blinn and press [7] to open a Render Tree. From the Nodes > Textures menu choose More… In the Browser, click the Paths button and choose the Binary Alchemy Shader Collection – Essential. Select the BA_fractal4d and press OK.

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Simulating an effervescent tablet using particles

Creating particles
The first think you’ll need is obviously a glass of water and a tablet, so start by opening the scene effervescent_tablet.scn from this issues CD. Press [4] to switch to the Simulate toolbar. Select the tablet and from the Create > Particles menu choose From Selection. In the particle PPG, change the settings as shown in the above screenshot (a high-resolution version can be found on the CD).

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