Autodesk 62205-051408-9001 User Guide - Page 390

14 Creating Particle Effects Transforming Deflectors Deflectors can be transformed and animated just like line emitters. For example, you can adjust deflector control points or move the entire deflector at different keyframes to control the particles created by a moving emitter. • To move it, drag a tangent handle. You can add and arrange several deflectors with thickness to slow down particles over an area as they go through the buffer zone. Use the appropriate bounce properties to create the desired damping effect. Deflectors can be curved like line emitters, but curved deflectors are essentially a series of line segments. The number of line segments used is relatively low, so the curve is approximate. Deflectors process better when there are fewer segments. To edit a deflector: 1. Click the Arrow tool (TAB) and select the deflector. 2. Use the Arrow tool options to edit the deflector. 3. As you edit the control points, you can do any of the following: • To add a control point, click on the line. • To delete a control point, select it and press DELETE. • To extend the tangent handles, CTRL-drag a control point. • To hide the tangent handles, CTRL-click a control point. • To break the tangent handles, CTRL-drag a tangent handle. Compositing with Particles There are several techniques and tricks you can use to composite particle effects into a composite in interesting and effective ways. Basic techniques include: • Using selections or masks to block particles • Tracking an emitter or its control points (for line emitters) to a clip • Using the Attach to Emitter option (see Attach to Emitter and Amount) • Using Preserve Alpha to use the alpha channel to control where particles are visible Other tricks are used to make 2D particles seem 3D and to simulate particle manipulators like wind, gravity, and friction. Using Selections with Particles You can use selections to block areas of the clip from showing particles. The Selection (or Paint) operator must be placed before (upstream of) the Particles operator. To block an area using a selection: 1. Add the Particles operator to the clip and set up the emitters you want. 2. In the Workspace panel, select the operator upstream of the Particles operator (for example, the Footage operator), and add a Selection operator. 374