Corona Proxy guide: Managing heavy models in 3ds Max scenes

Corona Proxy can be used in 3ds Max scenes to make objects with dense geometry easier to manage in the viewport and keep animated models playing at a reasonable frame rate. Chaos’s 3ds Max documentation describes the options for creating and exporting proxies, but does not specify a particular 3ds Max or Corona version. The steps below are based on the Corona Proxy and Corona Proxy Exporter workflows described in the documentation.

1. Choose a workflow before creating a proxy

A Corona Proxy can be created from an object in the scene or loaded as a previously saved proxy file. To use an object in the scene as the source, select Pick from scene in the Corona Proxy settings. For a file that has already been prepared, choose Load from file. Use Reload from disk when you need to reload the proxy from its source.

To export, first select the objects to be exported in Corona Proxy Exporter. Then choose one of these two options, depending on the project:

1. Collapse and export to single proxy file: Combines the selected objects into one proxy file. Combining many objects or models with a high face count into one file can make the export memory-intensive, and the process may take several seconds.

2. Export each node to separate proxy file: Exports each selected object as a separate proxy file. Use this option when objects need to be managed individually.

3. If you are creating a single file, Combined proxy name lets you assign a custom name to the combined proxy.

4. Replace source objects determines whether the source objects remain in the scene. When enabled, the source object is deleted and only the proxy remains in the scene; when disabled, both are kept.

You can also enable Warn for existing .cgeo files to avoid accidentally overwriting files. Use Export selected objects to start the export.

2. Adjust the viewport display to suit the scene

A proxy’s viewport display determines how it is represented during work, rather than changing the model’s render geometry. The documentation lists four methods: Solid Bounding Box, Wire Bounding Box, Point Cloud, and Full Mesh. Using Full Mesh with complex geometry does not improve viewport performance compared with displaying the original geometry. For this reason, Chaos documentation recommends Point Cloud: the model’s overall shape remains visible while viewport performance is taken into account.

For the Point Cloud percentage, the documentation gives 1%, 10%, 25%, 50%, 75%, and 100% as examples; it does not identify any of these as a single ideal setting for all scenes. Choose the number of visible points based on how closely the object’s shape needs to be represented in the viewport. The Point cloud displayed [%] setting is available only when Point Cloud is selected.

3. Consider memory and scene management together

The Keep in memory option in Corona Proxy prevents the model from being removed from RAM between renders. When enabled, it can reduce scene parsing time, but it also increases memory consumption. In scenes with limited memory, weigh the benefit of enabling it against that cost.

Cache in RAM in Exporter likewise aims to keep proxies in memory while working with 3ds Max and speed up scene parsing. The Chaos documentation specifically notes that this option does not affect render speed. Treat it as a way to speed up parsing while working with the scene, not as a method for reducing render times.

Use Batch convert to edit multiple proxies or convert proxies in the project folder to the latest Corona format. This converts proxies in the selected directory and its subdirectories to the latest .cgeo format; the source proxy files are preserved.

4. Match animated proxies to the timeline

If the proxy file contains animation data, playback can be enabled with Enable animation. To export animation, enable Animated in Exporter. Set the range to bake the motion using Active time segment or From frame / To frame.

For playback behavior, Repeat starts the sequence over after the last frame, while Ping Pong plays the frames forward and backward. Freeze out of range displays the first or last frame at times outside the animation range, while Hide out of range hides the proxy outside those ranges. Frame offset changes the animation’s starting position relative to the 3ds Max timeline, and Speed multiplier changes its playback speed. If the proxy file contains FPS information, Use file FPS uses that value for playback.

Common mistakes

• Displaying a complex model as Full Mesh and expecting the viewport to speed up; according to Chaos documentation, this method does not improve performance.

• Not accounting for RAM usage when enabling Keep in memory or Cache in RAM.

• Assuming Cache in RAM will increase render speed; the documentation states that this setting does not affect render speed.

• Expecting animation settings to work on a proxy with no animation data. Animation options are available only when the file contains animation data.

Impact on architectural and visualization workflows

In architectural scenes containing vegetation, furniture, or other densely modeled objects, proxies can make viewport work more manageable. Point Cloud lets you follow the approximate shape of an object without displaying the entire complex mesh. This makes it easier to balance visibility and performance, particularly when working with many heavy objects in a scene.

Before choosing an export method, offices should decide whether objects will be managed together or individually, and consider that exporting a single proxy can be memory-intensive for models with a high face count. Keeping proxies in RAM can help with scene parsing, but increases memory consumption. Since the documentation does not provide information about hardware requirements, licensing conditions, or specific software versions, these points should be checked for each project and installation.