VRayProxy

Search Keywords: proxy, mesh, VRayMesh

General

VRayProxy allows you to import geometry from an external mesh at render time only. The geometry is not present in the 3dsmax scene and does not take any resources. This allows the rendering of scenes with many millions of triangles - more than 3dsmax itself can handle.

Exporting a mesh to a file

Before you can import a mesh through a VRayProxy object, you need to create the mesh file first. You can do this in two ways:

Through the quad-menu: select the meshes you want to export, right-click in the viewport and select the "VRay mesh export" option. This will cause the VRay Mesh Export dialog box to appear.

Dialog from MaxScript: select the meshes you want to export and then type

doVRayMeshExport()

in the Listener window. This will cause the VRay Mesh Export dialog box to appear.

Direct export from MaxScript: select the meshes you want to export and then use the vrayMeshExport() function:

vrayMeshExport [meshFile:"<mesh file>"] [autoCreateProxies:true|false] [exportMultiple:true|false]

where <mesh file> is the name of the desired .vrmesh file. If the name does not contain a path, the default 3dsmax mesh path is used. If the name does not contain an extension, a .vrmesh extension is automatically appended. If the name does not contain a file name, the scene node name is used instead. If the autoCreateProxies option is not specified, by default the meshes are just exported, no proxies are created in the scene. If the exportMultiple option is not specified, the meshes are exported to multiple files by default.

The Mesh Export dialog

The Mesh Export dialog allows you to specify the mesh file as well as some export options.

Folder - this is the folder where the mesh file(s) will be created.

Export as single file - this option will take all selected objects and will merge them into one mesh file. This option also stores the transformations of the selected objects. When you import the file with a proxy object, it must be centered at the origin, if you want the objects to be in the same place. Also, since the imported mesh is rendered using the material of the proxy object, all meshes from the file will render with that material. You must use subobject materials and different material IDs if you want them to have different materials.

File - this is the name of the file. You don't need to specify a path. The Folder path will be used.

Export as multiple files - this option will create one file for each selected object. The name of each file is derived from the name of the correspondig object. The transformation of an object is not included in its mesh file, and the corresponding proxy must have the same transformation as the original object, if it is to appear in the same place.

Automatically create proxies - this option will create proxy objects for the exported meshes. The proxies will have the correct transformations and materials derived from the original objects. The original objects will be deleted.

Pressing the OK button will create the mesh files and the proxy objects. The export process may take some time, depending on the amount of geometry that must be processed.

The .vrmesh file format

Meshes are exported to a special .vrmesh file format. It contains all geometric information for a mesh - vertices and face topology as well as texture channels, face material IDs, smoothing groups, normals - in short, everything that is needed to render the mesh. 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.

It is important to realize that the mesh is in a "ready to render" format. No further modifications to the mesh are expected. You can't apply modifiers to the mesh, or animate it in any way except if you animate the position/orientation of the proxy object. There is no way to recover the original mesh from a .vrmesh file (this can be done in principle, but is currently not supported). Therefore, if you plan on doing modifications to the mesh, you should keep it in a 3dsmax file (which may be different from the file that gets rendered in the end).

Creating a proxy object

After you export a mesh to a .vrmesh file, you need a proxy object to represent it in the 3dsmax scene. To create a proxy object, go to the Create panel and choose the VRay category:

Click VRayProxy and then click in a viewport. A dialog box will appear that allows you to choose the .vrmesh file to import.

Proxy parameters

Mesh file - this is the source .vrmesh file.

Display - controls the display of the proxy in the viewports:

bounding box - the mesh is represented as a box in the viewports.

preview from file - displays the mesh preview info that is stored in the .vrmesh file.

Notes

The geometry generated by the proxy object is not modifiable. Any modifiers applied to the VRayProxy object will be ignored.
At present, the .vrmesh file cannot store animated meshes.
If you need to create several proxies linked to the same .vrmesh file, it's better to make them instances - this will save memory since the .vrmesh file will be loaded only once.
Materials are not saved in the .vrmesh file. Instead, the geometry will be rendered with the material applied to the VRayProxy object. This is because third party materials and procedural textures would be difficult to describe in a general way. In addition, you may want to edit the material independently of the mesh.
The resulting .vrmesh files can be rendered outside of 3dsmax - for example, by the standalone version of VRay.
Shadow maps will not include information about the proxy objects. If you want the proxy objects to cast shadows, you should use VRay shadows.

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