3ds Max 2012 Bible - Kelly L. Murdock [238]
FIGURE 19.7
Changing the Sample Radius value changes the amount of blur added to the scene.
Note
The Depth of Field effect is applied only to rendered scene objects. It is not applied to any background images. •
The Sample Bias value moves the blurring closer to the focal point (for higher values) or away from the focal point (for lower values). If you want to highlight the focal point and radically blur the other objects in the scene, set the Sample Bias to 1.0. A Sample Bias setting of 0 results in a more even blurring.
The Normalize Weights option allows you to control how the various passes are blended. When enabled, you can avoid streaking along the object edges. The Dither Strength value controls the amount of dither taking place. Higher Dither Strength values make the image grainier. The Tile Size value also controls dither by specifying the dither pattern size.
With lots of passes specified, the render time can be fairly steep. To lower the overall rendering time, you can disable the Anti-alias and filtering computations. These speed up the rendering time at the cost of image quality.
Tutorial: Applying a Depth of Field effect to a row of windmills
In the dry plains of Southwest America, the wind blows fiercely. Rows of windmills are lined up in an effort to harness this energy. For this example, you use the Depth of Field effect to display the windmills.
To apply a Depth of Field effect to a row of windmills, follow these steps:
1. Open the Depth of field windmills.max file from the Chap 19 directory on the DVD.
This file includes a windmill object (created by Viewpoint Datalabs) duplicated multiple times and positioned in a row.
2. Select Create⇒Cameras⇒Target Camera, and drag in the Top viewport from the lower-left corner to the center of the windmills. In the Left vewpoint, select the camera and move it upward, and then select the Camera Target and also move it upward to the upper third of the windmill's height, so the entire row of windmills can be seen. If the windmills don't fill the camera view, adjust the Field of View (FOV) setting.
Tip
You can select both the camera and its target by clicking on the line that connects them. •
3. Select the Perspective viewport, right-click on the viewport title, and select Views⇒Camera01 (or just press the C key) to make this viewport the Camera view.
4. With the Camera selected, open the Modify panel, enable the Multi-Pass Effect option, and then select Depth of Field in the drop-down list.
5. In the Depth of Field Parameters rollout, enable the Use Target Distance option and set the Total Passes to 15, the Sample Radius to 3.0, and the Sample Bias to 1.0.
6. Select the Camera viewport, and click the Preview button in the Parameters rollout.
This shows the Depth of Field effect in the viewport.
Figure 19.8 shows the resulting Depth of Field effect in the viewport for the row of windmills.
FIGURE 19.8
Multi-pass camera effects can be viewed in the viewport using the Preview button.
Using the Motion Blur effect
Motion Blur is an effect that shows motion by blurring objects that are moving. If a stationary object is surrounded by several moving objects, the Motion Blur effect blurs the moving objects and the stationary object remains in clear view, regardless of its position in the scene. The faster an object moves, the more blurry it becomes.
This blurring is accomplished in several ways, but with a multi-pass camera, the camera renders subsequent frames of an animation and then blurs the images together.
The Motion Blur Parameters rollout, shown in Figure 19.9, appears when