VRayProxy loads a geometry from a file on the disk at render time. The geometry is not present in the scene, and does not use up any resources, except for the viewport preview. This allows rendering scenes with many millions of faces, more than Cinema 4D itself can handle.

V-Ray Proxy loads alembic ( .abc ) and V-Ray Proxy ( .vrmesh ) files. Any mesh can be exported to an .abc  or .vrmesh file from Cinema 4D and then loaded as a proxy.

Meshes are exported to a special .vrmesh file format. This file contains all geometric information for a mesh, such as vertices and face topology, as well as texture channels, face material IDs, smoothing groups, and normals. In short, everything that is needed to render the mesh is included in the file. In addition, the mesh is preprocessed and subdivided into chunks for easier access. The file also contains a simplified version of the mesh used for preview purposes in the viewports. More information about the .vrmesh file format is available in the V-Ray SDK documentation that comes with the V-Ray for Cinema 4D installation.

See how to export and import proxy files at the Import and Export of V-Ray Proxy page.

Mesh File – The source .vrmesh file. Animated proxies can be stored either in one single file, or as a sequence of files with one file per frame. In the latter case, you can use the string <frame0n> in the file name to have it replaced with the current frame number at render time, where n is an integer number specifying the number of digits. For example, if you enter my_proxy_<frame04>.vrmesh as the file name, this is be expanded to my_proxy_0000.vrmesh for frame 0, my_proxy_0001.vrmesh for frame 1, and so on. If you use a sequence of files, the Playback type option is ignored, as V-Ray doesn't know how many frames are in the animation. The Playback speed parameter may also work unreliably with sequences of files.

Preview – Select the viewport preview mode from the drop down menu. This does not affect the final render.

Full Geometry – The full geometry of the mesh is visible in the viewport.
Preview Geometry – The mesh is represented as a low poly proxy preview, as defined in the .vrmesh file. A preview is generated on the fly for .abc files.
Bounding boxes – The mesh is represented as a box, scaled to fit the object in viewport.
Points – Represents the mesh as points.
None – No preview. This mode does not read any information from the proxy file and is useful for loading many and massive proxies for final scene assembly.

Flip Axis Mode – Determines how to read the proxy's vertical axis.

As Is – Remains as imported.
Y-up to Z-up – Switches the proxy's vertical axis from Y to Z. It allows aligning vertical axis of the proxy with the vertical axis in the scene in cases where the proxy was not exported from Cinema 4D or when loading Alembic files.
Z-up to Y-up – Switches the proxy's vertical axis from Z to Y.

Scale Multiplier – Allows the proxy geometry to be quickly scaled up or down. 

Open V-Ray Proxy Manager – Opens the V-Ray Proxy Manager window. See the V-Ray Proxy Manager section for more information.

Reset Texture Tags – Reverts the state to the original asset tags. The option is useful in case the asset is moved, the tags are deleted, or any other changes to the tags are done.

Playback Type – Specifies a playback mode. This option is ignored if you use a sequence of separate .vrmesh files.

Loop – The animation is looped by skipping to the first frame once it has finished.
Once – The animation is played once.
Ping-pong – The animation is looped by playing it backwards once the last frame has been reached and then playing it forward again when the first frame is reached.
Still – The animation is not played. Instead, just the Start offset frame is shown. 

Playback Speed — A multiplier for the speed of the animation. Putting negative numbers here makes the animation play backwards. This option may not work very well for sequences of .vrmesh files. 

Sequence Override – Allows you to manually override the start frame and the animation length to be read (in frames) for animations stored in sequences of .vrmesh files (where each frame of the animation is stored in a separate proxy file). Importing proxy sequences requires a special format that specifies how to match the frame padding in the file name. See the Mesh File option for more information..

Override Frame –

Sequence Start – Specifies the first frame of the animation.

Sequence Length – Specifies the length of the animation to be played.

Use Alembic Offset – When enabled, automatically uses the frame offset from the alembic file. When disabled, the frame offset is set manually.

Start Offset – Offsets the beginning of the animation by the given number of frames. You can use positive as well as negative values here. 

Smooth Uv – Smooths the mesh UVs when rendering as a subdivision surface.

Smooth Uv Borders – Smooths the mesh UVs at the borders when rendering as a subdivision surface.

First Map Channel – Specifies how to remap the mapping channels.

Hair

Tessellate Hair –  When enabled, tessellates hair strands for files containing hair. 

Hair Tessellation Length – Specifies hair edge length in pixels for smoothing hair strands.

Particles

Particle Render Mode – Controls how the particles in the proxy are rendered in the viewports. The available options are Spheres and Points.

Use Point Cloud – Enables the usage of point cloud data, if available.

Point Cloud Mult – Determines the way point cloud levels are loaded. A value of 1.0 means that the level to load is determined exactly by the distance from the camera to the object. A value smaller than 1.0 means that the level is of greater detail than required by distance. Values greater than 1.0 mean that the resolution of the level is smaller than the one determined by distance. A value of 0.0 means that no point cloud level is loaded and the original mesh is rendered instead.

Preview Faces – Allows you to specify how many faces are going to be used to show a preview of the proxy in the viewport.

Starting Object Path – Allows you to specify a starting path in the Alembic file; only objects below that path are rendered. The path may start with ABC/ or it may be omitted.

Instancing – Determines how alembic instances are read:

Disable Instancing – No instancing takes place. If there are instanced objects in the alembic file, the whole geometry is copied.
Instantiate Duplicated Objects – Duplicate objects are instanced.
Instantiate Duplicates and Assign Unique Material IDs – Duplicate objects are instanced and unique material IDs are assigned to each instance.

Recompute Bounding Box – Enabling this check box forces V-Ray to recompute the bounding box for the geometry before rendering. When this is off, V-Ray uses the bounding box specified in the Alembic file. However, sometimes these bounding boxes are not correct, and in that case the rendering is also incorrect. To avoid such issues, enable this option. Note that this option might slow down the rendering. 

Compute Normals – This option allows you to force smooth normals on the geometry in case they are not originally smoothed.

Smooth Angle – When the Compute normals option is enabled, this specifies the angle, below which normals are smoothed.

Flip Normals – Reverses the direction of the normals.

Hair Width Multiplier – This multiplier allows you to control the hair width during rendering.

Particle Width Multiplier – Controls the size of the particles when rendering.

Velocity Multiplier – Controls the length of the motion blur when rendering.

Geometry

Subdivide All Meshes – Subdivide the meshes before rendering using the OpenSubdiv library.

Subdivision Type – The type of subdivision used:

Catmull-Clark – The default subdivision method that can handle meshes with arbitrary polygons (triangles, quads, etc)
Loop – This subdivision method works with triangles only

Subdivision Level – The number of subdivision levels.

Subdivide UVs – Allows you to choose whether or not the UVs of the object are subdivided at the borders.

Preserve Geometry Borders – Specifies whether geometry borders are preserved or not.

Preserve Map Borders – Specifies how to handle subdivisions of UV coordinates at UV seams, when Subdivide UVs is enabled. The possible values are:

None – UVs are always subdivided, regardless of whether they are on a UV seam or not.
Internal – Only preserve UVs if they are on an internal UV seam.
All – Does not subdivide UVs on UV seams.

Use Alembic Transform – When enabled, uses the transform properties from the alembic file. Otherwise, uses the transform properties of the proxy object.

Layers

The Alembic layers feature allows modification of a selected alembic proxy by adding layer files on top of it. Each layer transforms the proxy with a different set of properties. These transformations include adding properties to a shape (e.g. UV mapping of an object that has no UVs), overriding properties, adding new objects, pruning objects or properties, replacing an object's (or properties') hierarchy with a new one, etc.

You can combine different cache files. Whenever the same object is found in a layer, all of its properties are considered.

The V-Ray Proxy Manager lists all of the imported proxies in the scene and allows easier management of each.

You can enable or disable the visibility of a proxy or part of it.

The properties section provides quick access to the selected proxy's options.

You can search for a particular object by name from the search field.

The proxy file structure is represented in a tree view with its full hierarchy. You can select individual elements and assign visibility or material overrides.