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Render Proxy

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The Render Proxy function allows users to completely remove one or more Mesh Item layers within a scene, offloading them to an external file that won't be loaded again until render time. The saved layers will be replaced within the master scene by a simple bounding box, or if the user wishes an alternate version of the saved file used just for display. This is meant to facilitate two workflow processes, the replacement of high resolution meshes by a bounding box in the scene file will produce a lighter file, making for smoother navigation and faster file save times, also this allows additional work to be applied to the saved proxy file externally. When the modified file is loaded at render time, any updates saved to the proxies will be reflected in the final rendered image.


The recommended workflow for creating Proxy items is that they originate in a given scene as a regular Mesh Item layer. The Mesh Item is converted to a Render Proxy by RMB+clicking on the target Item layer or layers in the Items list, opening the contextual menu. Select the "Convert to Proxy" command, this opens a OS specific dialogue allowing users to specify the Proxy file location and name. After clicking the 'Save' button, MODO opens the following dialogue-

Render Proxy Panel

The 'Filename' option will always reference the location defined in the previous OS dialogue. There is also the additional option to convert the Proxy item to a Static Mesh on exporting. Generally users will keep this option disabled as converting a Mesh to a Static Mesh is destructive. However it can be a good option to enable when it won't be necessary to edit the externalized file any further; a Static Mesh cannot be directly edited nor deformed although it does create a smaller file size. Pressing OK will write the Mesh Item out as an external LXO scene file that contains the layers that were selected when the command was invoked. Each of the resulting layers are now represented by just the bounding box. When creating Proxies the resulting item(s) will inherit any transform values or keyframed animation that the original mesh had, keeping them in the master scene, but deformation based animations will not be applied as the mesh is no longer part of the scene. Selecting the bounding box , the Proxy item in the Items list provides a number of options in the Properties viewport panel-

Render Proxy

PanelName: This data field displays the current item name. Users may easily change it by LMB-clicking within the field and typing the new name.


Position: An Item transform that allows the user to numerically position the item in XYZ space. By default, Position transforms originates from the Center position.

Rotation: An Item transform that allows the user to numerically set the rotation of the item. By default, Rotation transforms originate from the Center position.

Order: Allows the user to set the order that rotations are applied to the camera item. Changing the order that rotations are applied can sometimes help to reduce or eliminate gimbal lock.

Scale: An Item transform that allows the user to numerically set the size of the item. By default, Scale transforms originate from the Center position.

Reset: Resets the selected transform values to (0,0,0) returning the items back to their default state.

Zero: Resets the chosen transform property values to '0', leaving the 'Center' position and Mesh position intact.

Add: Transform Items are the channel groups associated to an item that store its transform values, controlling its position, rotation and/or scale. By default, new items do not have any transform items associated with them (even though they are visible here within the Properties panel). This is useful as an optimization as only the necessary transforms are added on an as-needed basis, reducing scene overhead. There are several ways to add them. One is by simply transforming the target item with one of the various transform tools (or by editing the values input fields). This action will cause the particular transform item to be added automatically to the 'Channels' viewport list. The 'Add' function here can also be used to add the selected set of transforms to the Channel list while keeping the default 0,0,0 values (a necessary step for 'Referencing', in order to override the channels, they must first exist).


Scene: The 'Scene' option represents the path to the LXO file containing the original Proxy layers exported with the 'Convert to Proxy' command. Should it be necessary to move the Proxy file, users can use this option to reinstate the connection by locating the files new location with the 'Browse' option.

Render Item: The 'Render Item' option represents the specific Item layer name in the Proxy LXO file that is loaded at Render time.

Preview Item: By default a Render Proxy item is represented in the 3D viewport by its bounding box. When something more representational of the actual geometry is required (such as for animation purposes), the 'Preview Item' option provides for an alternate Mesh Item layer from the Proxy LXO that will be displayed in the 3D viewport of the master scene in place of the bounding box. This can be anything including the actual proxy mesh - but that defeats the purpose of the Proxy. Still, it will be most beneficial if the preview Proxy is representational of the geometry that will render. This can often be created by opening the saved Proxy LXO separately, duplicating the Render Proxy item layer and deleting any unnecessary geometry in the new duplicated layer. The 'Reduction Tool' may also prove to be useful in generating reasonable Preview geometry. Next, save the Proxy LXO file and then in the master scene specify the reduced geometry layer here with the 'Preview Item' option.

Preview Rendering: Since a Render Proxy item isn't part of the actual master scene and is only loaded into memory at render time, it also won't show up in any of the Preview or RayGL viewports. This can be remedied for Preview by enabling the 'Preview Proxies' option, but keep in mind this will keep the Render Proxy loaded into memory eliminating any memory savings benefits. The 'Preview Rendering' option provides users a means to specify an additional optional mesh item layer within the Proxy LXO to be used exclusively for Preview rendering in place of the actual Proxy mesh.

Replace Shaders: When creating a Proxy item, all related shaders will remain in the master scene, but they are also cloned into the Proxy scene when it is saved. The cloned surfaces in the 'Proxy' item file will be the surface settings that are referenced for rendering. When the 'Replace Shaders' option is enabled users can modify the shading information contained in the Master Scene to modify the surfaces, providing an override to the settings of the Proxy.

Unload Proxy Item: The 'Unload Proxy Items' command removes all Proxy data from memory and reinitializes it, setting it to the initial state as when it was generated.

Restore from Proxy: The 'Restore from Proxy' command will reinstate the Mesh item layer(s) as Proxies to full fledged Mesh layers. This command will not remove the saved file from disc. Also, any changes made to the Proxy file will also be reflected in the resulting geometry, including if the file was saved as a Static Mesh.


Render Proxy Workflow Considerations

Once a layer is converted to a Render Proxy in a scene, the original geometry layers will only be loaded at render time, the geometry itself will no longer be part of the master scene, including all that that implies; this will exclude any associated vertex maps and other relevant associated data will not be accessible in the master scene. Because of this Render Proxies cannot be deformed using any of MODO's Deformers since the geometry isn't actually part of the scene until Render time. Transform animations, such as move, scale and rotate, when applied to the Proxy layer, will render just fine.

Due to the global nature of shading in MODO, when a Proxy item is created, its related Shader Tree layers will remain in the Master scene, as they could very easily still be a part of another surface. Nevertheless further editing of these layers will have no affect on the shading of the Proxy item, only modified settings within the Proxy file itself will be reflected in the Rendered image, unless the 'Replace Shaders' option is enabled acting as an override. If there is no need to further edit the Proxy surfaces in the master scene and it is desirable to remove the extraneous Shader Tree layers, applying the command found in the menu bar under "Texture > Purge Unused Materials" will remove any unused surfacing. If the surfaces remain, it is likely because they are still applied elsewhere or they are masked using the non-default (other than Material) tags.



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