What Are Models?

 
 
 

Models are a powerful way of organizing objects in your scenes and projects. They act as a container for objects, usually hierarchies of objects, and many of their properties. Models contain not just the objects' geometry but also the function curves, shaders, mixer information, layer and partition memberships, and other properties. They can also contain internal expressions and constraints; that is, those expressions and constraints that refer only to elements within the model's hierarchy. In addition, models can contain groups.

   

"Club bot" model structure contains many things that define the character.

Models are like "mini scenes" that can be easily reused in scenes and projects. In fact, exporting and importing models is how you can copy between scenes.

Every scene contains at least one model, called the Scene_Root, which is the parent of all other models. You can create as many other models as you like, even nesting them within each other in a hierarchy (that is, a model can be the child of another model). Models are nulls that act as the root of a hierarchy, and they also have other properties.

In the explorer, models are distinguished by special icons . To make them easier to select, you can even set the explorer to show only models, which greatly simplifies the representation of your scene.

NoteIf you want to use the animation mixer, you should always create a model for the objects you want to animate. For more information, see Models and the Mixer. You can share or copy actions between models as described in Sharing Actions between Models.

Types of Models

There are two types of models: local and referenced. Local models are specific to a single scene, but referenced models are external files that can be reused in many scenes.

Local Models

Local models are specific to a single scene and are saved within the scene file. They provide a way to organize a scene, allowing you to take advantage of namespaces so that different models can contain objects with the same names.

NoteIf you open a scene with externally stored local models (.mdl files) that was created in an earlier version of Autodesk Softimage, the models are converted to internal storage and their data is saved directly in the scene.

Referenced Models

Referenced models are exported models that are linked to external files. Any changes you make to the exported model will be reflected in your scene the next time you open it or update the reference.

You create a referenced model by exporting a model as an .emdl file, and then importing it as a referenced model in another scene. Each referenced model can be linked with up to three different .emdl files for working at different resolutions: low, medium, and high.

You can use referenced models in limited ways (for example, you can animate objects within the model, but not delete them), but they provide greater flexibility in sharing resources within a workgroup and keep scene file size to a minimum. For more information, see Using Referenced Models.

Models and Namespaces

Each model maintains its own namespace. This means that each object in a model's hierarchy must have a unique name, but objects in different models can have the same name. For example, two characters in the same scene can both have chains named left_arm and right_arm if they are in different models.

All models exist in the namespace of the scene. This means that each model must have its own unique name, even if it is within the hierarchy of another model.

Namespaces let you reuse animations that have been stored as actions. If an action contains animation for one model's left_arm chain, you can apply the action to another model and it automatically connects to the second model's left_arm. If your models contain elements with different naming schemes, for example, LeftArm and L_ARM, you can use connection mapping templates to specify the proper connections. Actions and templates are described in Actions.

Integrating 3D Models with Property Overrides

You can maintain an imported model's attributes without using referenced models by gathering all the applied property sets, such as materials and textures, and bundling them into a single preset called a property override. Once you delete the old model and re-import the new one, you can apply this preset to the model and effectively override all the properties and characteristics that existed on the original.

This method provides a different kind of flexibility because you can apply property overrides to different but similarly structured models. Also, you can use property sets with imported models created in other 3D applications.

For more information on overrides, see Overriding Properties.

Maintaining the Model's Fundamental Structure

Re-imported models can receive any property that existed in the previous model, as long as the new model's hierarchy respects that of the original. For example, the texture on a robot's hand is not reapplied if one or more joints connecting the hand to the body have been removed.

Overview of Models

The steps below give a quick overview of working with models:

  1. Create a local model containing the selected objects. See Creating Local Models.

    At this point, the model has its own namespace and its own mixer, so it can share action sources with other models in the same scene. It can also be instantiated or duplicated within the same scene. If that's all you need a model for, you do not need to export and import it.

  2. Export the model as an .emdl file. This step is necessary only if you want to reuse the model in other scenes. See Exporting Models.

  3. Import the model into a different scene. You have two options: import as a local model or import as a referenced model.

    • An imported local model behaves just like a model created within the scene — it does not "remember" that it was originally imported from elsewhere. As always, it has its own namespace and mixer, and can be instantiated, duplicated, and so on. See Importing Local Models.

    • A referenced model maintains its link to the external .emdl file. You can change the .emdl file, and the referenced model automatically updates in all scenes that contain it. Referenced models also allow you to specify different .emdl files for different levels of detail, thus speeding up your interaction and simplifying your view of the scene. See Using Referenced Models.