mr Proxy Object

mr Proxy Object

Set mental ray as the current renderer. - - Create panel-(Geometry) -mental ray - Object Type rollout-mr Proxy button

The mr Proxy object is intended for use in large scenes to be rendered with mental ray.

This object type is useful when scenes contain many instances of an object, such as an auditorium with hundreds or thousands of instances of a seat model. It is also particularly useful for objects with extremely high polygon counts, in that it obviates both the conversion to mental ray format and the presence of the source object at render time, thus saving time and freeing up a great deal of memory for rendering. The only drawbacks are the reduced fidelity of the proxy object in the viewports and the inability to edit proxies directly.
The basic usage of the mr Proxy object is that you create and optionally animate the “source” object, apply a material, and then save a copy to disk for possible future modification. Next, you convert the object to mr Proxy format and write the proxy to a disk file or series of files, after which it appears in the viewports as a point cloud (a set of vertices showing the object size and approximate shape). Finally, you delete the source object, as its presence in the scene is no longer necessary. You can then use the mr Proxy object like any object in the scene, instancing it, transforming it, and so on. When you render, mental ray loads the disk files and uses the geometry defined therein. However, if you need to modify it (such as changing a modifier parameter, or editing a sub-object), you need to load the source object, modify it, reconnect it to the proxy object, and rewrite the files.

NoteUsing Select Similar with an mr Proxy object selects all mr Proxy objects, even if they use different source objects.

Procedures

To use the mr Proxy object:

1. Make sure mental ray is the active renderer.
2. Create or load the object that is to serve as the source object. Apply any necessary modifiers and material. Be sure to save a copy for future reference.
3. Add an mr Proxy object. Until you define the source object, the mr Proxy object appears in the scene as a wireframe cube.
   
4. Go to the Modify panel. The mr Proxy object requires that you specify the source object from the Modify panel.
   
5. Click the source object button, which currently reads “None,” and then select the source object. The name of the source object appears on the button.
   
   TipIf you plan to modify the source object, do so before converting it to mr Proxy format. Because the mr Proxy geometry is loaded by mental ray at render time, the renderer ignores any modifiers that change the geometry. The one exception is the Skew modifier, which affects the object’s transformation matrix rather than its sub-object geometry, and thus can modify a proxy.
6. Click the Write Object To File button, enter a file name, and click Save. This opens the mr Proxy Creation dialog, which lets you set parameters for the proxy object file, including animation frames and preview settings. Change settings as necessary and then click OK to continue.
   The file is saved in the MIB format and its path and file name are placed in the Proxy File field. After you save the file, the Display group shows the proxy geometry and the viewport shows the object, by default, as a point cloud: a group of vertices that roughly defines the object’s shape. You can change the number of points in the cloud and use a bounding box to represent the object, with or without the point cloud. (When the point cloud is on, you can toggle the bounding box, but when you turn off the point cloud, the bounding box always displays.)
   
   
   
   
   To use materials with the mr Proxy object:
   When you convert an object to mr Proxy format, the proxy does not inherit the object’s material. An efficient way to handle this is with the XRef material.
   
   1. Create or load the object that is to serve as the source object. Apply any necessary modifiers and material, and then save a copy.
   2. Create the mr Proxy object and then convert the source object, as described in the preceding procedure. Delete the source object.
   3. Apply an XRef material to the proxy object.
   4. Set the material to use the material from the source object file you saved in step 1. Then, to modify the material on the proxy, load the source object, edit its material, and save the file. Because the material on the proxy object is externally referenced, it updates automatically.
   Example: To use an animated source object:
   The mr Proxy object supports vertex-level animation as well as topological changes in the source object. For example, you could create a fluid simulation with a particle system to which BlobMesh is applied, and then bake it out to a series of mr Proxy files. This procedure gives an example of how to use this feature.
   
   1. Create a source object and add vertex-level animation. For example, you could apply the Bend modifier and then set keys for different values of the Angle parameter.
   2. Add an mr Proxy object.
   3. Go to the Modify panel, click the source object (“None”) button and then select the object from step 1.
   4. Click the Write Object To File button, enter a file name, and click Save. On the mr Proxy Creation dialog, choose either animation option (Active Time Segment or Custom Range) and, if you like, toggle the Preview Generation switches. Click OK to continue.
      3ds Max writes a pair of files (geometry and thumbnail) for each animation frame.
      
   5. You control animation playback in the Proxy object with the Animation Support group settings. When you save or load an animated Proxy, 3ds Max automatically enables the On check box in this group and sets Frames to the number of frames in the animation. You can change the value to the number of frames you want to use from the animation. Also, you can adjust the rate at which the animation appears in the proxy object by adjusting the Replay Speed value, and change the frame at which the playback begins with the Frame Offset parameter. Last, to have the animation play back and forth, turn on Ping-Pong Replay.