Setting Up the Scene and Models for Rendering
To make the rendering process go smoothly in Behavior, you can associate scene elements and a set of final rendering target models in Softimage to the actors in the Behavior simulation. This lets you use low-resolution models for an actor’s simulation in Behavior, but associate these actors to their high-resolution counterparts which are used only for rendering. Target render models are typically used only for animated digital actors.
You do this by first setting up your Softimage scene (see below) and then using the Render Setup command to save its data in a set of MI and dotXSI files. The MI file format describes a scene to mental ray for rendering and is the medium for moving data through the Softimage-to-Behavior-to-mental ray rendering pipeline. By importing these files into Behavior, you can simplify the process of generating the mental ray data that is used for the final rendering of the Behavior simulation.
The Render Setup command can be used only for the scene’s current pass. To generate render data for other passes, you need to switch to that pass and repeat the steps in this section.
For more information in general about rendering using mental ray, see Rendering.
Setting Up the Scene in Softimage
You need to set up the camera motion, lighting, effects, scene elements, etc. for the Behavior simulation. In addition, you set up the target render models for the digital actors in the simulation.
To set up the Softimage scene for rendering to MI and dotXSI files
1. Set the scene’s current pass to the one you want to render.
2. Load the background (simulation environment) geometry into the Softimage scene—this includes all objects, cameras, and lights that you want to be in the Behavior simulation. Any of these objects can be animated.
3. Load all the target render (high-resolution) models into the Softimage scene. For each actor class (the “master” actor from which instances are created in Behavior), you can have multiple target render models.
The target render models must have matching node names with the Behavior actor in terms of the relevant animated parts.
Make sure that each target render model is contained within a Model node.
4. Put all the target render models into a group.
When you’re ready to generate the files for rendering, you use the Render Setup command. This command generates MI files for the frames of the scene, along with dotXSI files of the target render models for their geometry and enveloping information. As well, an accompanying render setup file (.bvrn) is created to help Behavior understand the data that is in the MI and dotXSI files.
After you have created these render files, you bring them into Behavior where they are read during the simulation. The MI files are then updated with references to the digital actors in Behavior.
To generate the render setup files
1. Set the scene’s current pass to the one you want to render.
The Render Setup command can render only the current pass. To generate render data for other passes, you need to switch to that pass and repeat these steps. You can set the rendering options for each pass as you like.
2. Choose File > Render Setup from the Behavior toolbar.
3. In the dialog box that appears, enter a path and File name for the *.bvrn file which accompanies the generated MI and dotXSI files and describes the render setup to Behavior.
4. From the Target list, select the group that contains all the target render (high-resolution) models you want to map.
5. Set the desired Frames that you want to capture for the simulation shot. If there is no animation for the background (cameras, lights, props, etc.), set the Start and End frames to 1.
6. Select the Map - Enable option if you want to map the target render models to an actor in Behavior.
Then enter the name of the Actor Class to which you want to associate the target render models. An actor class is the “master actor” from which many instances can be created.
For each Behavior actor class, you can have multiple target render models. You can then map a different target render model to each instance. For example, if you had two target render models for an actor, you could map one to all even-numbered instances of the actor and the other to all the odd-numbered instances.
7. Click the Generate button.
The scene is processed and the MI file, dotXSI file, and BVRN render setup file are generated in the folder that you specified.
8. You can now import these files into Behavior to add your simulation data to the MI files.
For the final render of the Behavior simulation, you generate MI files from Behavior and batch render them using ray3.exe, the standalone mental ray rendering application, in which a special geometry shader adds the geometry of the digital actor instances into the shot.
Autodesk Softimage v.7.5