Chapter 47: Compositing and Render Elements

After you've completed your scene and rendered it, you're finished, right? Well, not exactly. You still have post-production to complete-that's where you work with the final rendered images to add some additional effects. This phase of production typically takes place in another package, such as Photoshop, Autodesk's Combustion, or Adobe's After Effects, and understanding how to interact with these packages can be a lifesaver when your client wants some last-minute changes (and they always do).

You can set Max to render any part in the rendering pipeline individually. These settings are called render elements. By rendering out just the Specular layer or just the shadow, you have more control over these elements in your compositor.

Using External Compositing Packages

Before delving into the Video Post interface, let's take a quick look at some of the available compositing packages. Several of these packages have direct links into Max that can be used to give you a jump on the post-production process.

Compositing with Photoshop

Perhaps the most common tool for compositing images is Photoshop. Photoshop can bring multiple images together in a single file and position them relative to one another. Working with layers makes applying simple filters and effects to the various element pieces easy.

Figure 47.1 shows Photoshop with several separate pieces, each on a different layer.

Figure 47.1: Photoshop is an important compositing tool for static images.

To composite images in Photoshop, you need to load all the separate images into Photoshop and then select the portions of the images that you want to combine. When saving image files in Max, be sure to include an alpha channel. You can see the alpha channel in the Rendered Frame window if you click the Display Alpha Channel button, as shown in Figure 47.2.

Figure 47-2: The Rendered Frame window can display an image's alpha channel.

In Photoshop, you can see an image's alpha channel if you select the Channels panel in the Layers palette. Selecting the alpha channel and using the Magic Wand tool makes selecting the rendered object easy. After it's selected, you can copy and paste the rendered image onto your background image as a new layer.

Note 

Not all image file formats support an alpha channel. When rendering images to be composited, but sure to use an alpha channel format such as RLA, RPF, PNG, or TGA.

After all your images have been positioned on the background image, you can apply a Filter, such as a Gaussian Blur, to smooth the edges between the composite images.

Video editing with Premiere

Photoshop works with still images, but if you work with animations, then Adobe has Premiere to help with your video editing needs. The editing that Premiere makes possible includes patching several animation clips together, adding sound, color-correcting the frames, and adding transitions between animation clips.

Within Premiere, various animation clips can be imported (or dragged directly from Windows Explorer) into the Project panel. From here, the clips can be dropped onto the Timeline in the desired order. The Monitor panel shows the current animation or individual animation clips.

Sound clips can be dropped in the Timeline in the Audio track. The Title menu also can be used to add text to the animation. Another common activity in Premiere is to add transition effects between clips. This is done by clicking the Effects tab in the Project panel, selecting a transition effect, dragging the effect to the Timeline, and dropping it between two animation clips.

When the entire sequence is completed, you can render it using the Sequence Render Work Area menu command. The completed animation file then can be saved using the File Export menu command.

Tutorial: Creating a montage of Space Warp animations

In this example, we combine several animations into a single animation sequence. To create a montage of several animations using Premiere, follow these steps:

1. Open Premiere, and drag the Space Warp animations from the Chap 47 directory on the DVD to the Project panel.

2. Select all five animation clips, and drag them to the Video 1 row in the Timeline panel. Select Sequence Zoom In four times to space the animations out in the Timeline panel so they are visible.

3. If you want to change the order of the animation clips, just drag them to the desired position in the Timeline panel. Make sure that they run consecutively.

4. Click the Effects tab in the Project panel, and open the Video Transitions folder. Select one of the transition effects, and drag it from the Project panel to the Timeline panel. You can drop a different effect where each animation clip meets its neighbor.

5. Click the Play button in the Monitor panel to see the resulting animation sequence. If you're comfortable with it, select Sequence Render Work Area to render the final sequence.

6. When the rendering completes, save the animation using the File Export Movie menu command.

Figure 47.3 shows the Premiere interface with the animation clips loaded and positioned in the Timeline panel.

Figure 47-3: Premiere can be used to combine several animation sequences together.

Video compositing with After Effects

If you need to add a little more to your animations than just transitions, you should look into Adobe's After Effects. After Effects lets you composite 2D and 3D clips into a single image or animation. You can paint directly on the animation frames, add lights and cameras, and create visual effects such as Distort, Shatter, and Warp.

After Effects includes a library of resources much like those found in Premiere. These resources can be positioned on a Composition pane. Effects applied to the loaded animation clip are listed in the Effects panel along with all the effects settings.

After Effects includes many of the same tools used in Photoshop and Illustrator. These tools let you paint and select portions of the animation clip as if it were a still image, but the results can be added or removed over time.

Tutorial: Adding animation effects using After Effects

Some effects are much easier to add using a package like After Effects than to create in Max. A good example is adding a blurry look and the waves coming from a heat source to the melting snowman animation created in Chapter 32.

To add video effects using After Effects, follow these steps

1. Open After Effects, and drag the Melting snowman.avi file from the Chap 32 directory to the Project panel.

2. Select Composition New Composition, select the NTSC, 640 × 480 option from the Preset list, and click OK.

3. Drag the Melting snowman.avi file from the Project panel, and drop it on the Composition pane.

4. With the animation selected in the Composition pane, select Effect Distort Wave Warp. The Wave Warp effect appears in a panel. Set the Wave Height to 4, the Wave Width to 30, the Direction to Vertical, and the Wave Speed to 1. This adds a heat wave effect to the entire animation.

5. Select Effect Blur &Sharpen Gaussian Blur, and set the Blurriness value to 3.0.

6. In the Timeline panel, drag the Work Area End icon so that it coincides with the end of the animation.

7. Select Composition Make Movie. In the Render Queue dialog box that opens, click the Render button to render the animation with its effects.

Figure 47.4 shows the After Effects interface with the animation clip loaded.

Figure 47-4: After Effects can add special effects to an animation sequence.

Introducing Combustion

Autodesk offers an end-to-end solution for production houses to complete their work; on the receiving end of Max is a product called Combustion. Combustion is a different animal from Max, but its array of weapons is just as deadly in a slightly different arena. The biggest difference between Combustion and Photoshop is that Combustion can handle animations and Photoshop can work only with static images.

Combustion enables motion graphics, compositing, and visual effects, which doesn't sound too different from what Max does, except for that funny word-compositing. If you think of the final rendered image produced using Max as just an image that needs to be combined with other elements such as text, logos, other images, or even a DVD menu, then you're starting to see what post-production teams know. Compositing is the process of combining several different elements into a finished product. Positioning these elements can even be done in 3D by placing images behind or in front of other images or in time by working with animations.

Figure 47.5 shows the Combustion interface. Right off the bat, you should notice how different it is from Max.

Figure 47-5: Combustion has a unique interface, much different from Max.

But wait, you say; this is a book about Max, not about Combustion. Yes, but Combustion is integrated with Max very nicely, and that is what I want to show. Several key integration points include Combustion maps and Render Elements.

Using Combustion maps

If you apply a Combustion type map to the Diffuse map channel of a material, then the Combustion Parameters rollout, shown in Figure 47.6, appears. Clicking the Edit button in the rollout actually opens Combustion and lets you create a new workspace.

Figure 47-6: Combustion maps work between Max and Combustion.

If you select a Paint type workspace, then you can paint right on the composite object in Combustion, and the painted map shows up in Max. Figure 47.7 shows a simple spiral shape painted in Combustion using its tools. Figure 47.8 shows a magnified sample slot in Max that has the same painted shape.

Figure 47-7: Combustion maps painted in Combustion show up in Max.

Figure 47-8: Shapes that are painted in Combustion show up in Max.

The Live Edit section of the Combustion Parameters rollout includes features that you can access from Combustion. The Operator button lets you select and update an operator from Combustion to apply to the texture map. The Unwrap button shows an unwrapped mesh in Combustion, allowing you to easily paint precisely. The Paint button lets you paint directly in the viewports using Combustion's Paint tools, and the Filtering options let you specify the type of anti-aliasing to use.

Using Render Elements with Combustion

At the bottom of the Render Elements rollout found in the Render Elements panel of the Render Scene dialog box is an option to Output to Combustion. If this option is Enabled, then you can specify a filename for the Combustion files that are generated, and the Render button actually creates the Render Elements and saves them in a Combustion Workspace (.CWS) file.

Using other compositing solutions

In addition to the packages mentioned here, several other compositing solutions are available. Another popular compositing package is Digital Fusion. Most of these products are similar enough, but look through the feature set before buying a solution to make sure that it meets your needs.