This page provides information on the VRayProxy node.
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Page Contents
Overview
VRayProxy imports geometry from an external mesh at render time only. The geometry is not present in the scene, and does not use up any resources. This allows the rendering of scenes with many millions of faces, more than Houdini itself can handle. The node can load alembic (.abc) and V-Ray proxy (.vrmesh) files.
If you wish to import a mesh through a VRayProxy node, the mesh must first be exported to a .vrmesh file. See the Create V-Ray Proxy and Proxy Export | rop_vrayproxy pages for details.
UI Path: ||obj Network|| > Geometry node > V-Ray > V-Ray Proxy Import
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. More information about the .vrmesh file format is available in the V-Ray SDK documentation that comes with the V-Ray for Maya installation.
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 other than animating 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 Maya file (which may be different from the file that gets rendered in the end).
Alembic Support
The VRayMesh node can also load and render Alembic files (.abc). The supported geometry types are polygonal meshes (without subdivision surfaces), spline curves and particles.
V-Ray will recognize velocity information for motion blur if it is stored either as standard Alembic velocity, or as a 3D vector array property called arbGeom.v, arbGeom.velocities or arbGeom.velocity. Additional Alembic color sets are imported as mapping channels with indices greater than 0 (i.e. 1, 2 etc). It's also possible to use such a color set for velocity. The VRayMesh has some additional parameters related to Alembic files. See the Alembic Proxy Parameters section of the Import V-Ray Proxy page for more details.
Parameters
Load – Selects how the mesh will be loaded.
Bounding Box – The mesh is loaded as a box scaled to fit the object in viewport.
Preview Geometry – The mesh is loaded as a low poly proxy preview as defined in the .vrmesh file.
Full Geometry – Loads the original mesh.
Display As – Specifies the viewport preview mode. This does not affect the final render.
Full Geometry – Loads the original mesh as the preview.
Point Cloud – Previews the mesh using its point cloud data if available.
Bounding Box – Previews the mesh as a box scaled to fit the object in viewport.
Centroid –
Hidden – Does not display a preview.
Missing File – Specifies how V-Ray will handle a missing file:
Report Error – V-Ray reports an error.
No Geometry – V-Ray does not load any geometry and does not report an error.
Reload Geometry – V-Ray attempts to reload the specified geometry.
V-Ray Proxy Settings
File Name – 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.
Playback Type – Specifies a playback mode. This option will be ignored if you use a sequence of separate .vrmesh files.
Loop – Loops the animation by skipping to the first frame once it has finished.
Once – Plays the animation once.
Ping-pong – Loops the animation by playing it backwards once the last frame has been reached and then playing it forward again when the first frame is reached.
Still – Does not play the animation. Instead, just the Start offset frame is shown.
Sequence Override – Allows you to manually specify which part of the animation to be played.
Playback Speed – A multiplier for the speed of the animation. Putting negative numbers here will make the animation play backwards. This option may not work very well for sequences of .vrmesh files.
Start Offset – Offsets the beginning of the animation by the given number of frames. You can use positive as well as negative values here.
Sequence Start – Specifies the first frame of the animation.
Sequence Length – Specifies the length of the animation to be played.
Primary Visibility – Controls the total visibility of the object in the final render.
Scale – Specifies the size scaling factor.
Flip Axis – Transforms the proxy from the Y-up to Z-up (and vice versa) coordinate system.
Smooth Uv Borders – When enabled, smooths UVs at the mesh borders when rendering the mesh as a subdivision surface.
Smooth Uv – When enabled, smooths UVs when rendering the mesh as a subdivision surface.
Compute Normals – When enabled, V-Ray generates and saves information about the normal of each vertex. This requires additional memory but speeds up the shading calculations during rendering.
Smooth Angle – When Compute Normals is enabled, specifies the angle amount below which normals will be smoothed.
Recompute Bounding Box – When enabled, the bounding box of the mesh will be recomputed. When disabled, the bounding box specified in the file will be used.
Preview Faces – Allows you specify how many faces are going to be used to show a preview of the proxy in the viewport.
Use Face Sets – Turns face sets on or off.
Use Full Names – When enabled, reads the full path instead of only the name.
Starting Object Path – Specify a starting path in the Alembic file; only objects below that path will be rendered. The path may start with ABC/ or it may be omitted.
Hair Width Multiplier – This multiplier allows you to control the hair width during rendering.
Visibility Lists Type – Specifies whether the list includes or excludes objects.
Exclude – The selected object in the list will be invisible.
Include – Only the selected object in the list will be visible.
Hair Visibility Lists Type – Specifies whether the list includes or excludes hair objects.
Exclude – The selected object in the list will be invisible.
Include – Only the selected object in the list will be visible.
Flip Normals – Reverses the direction of the normals.
Particle Width Multiplier – Controls the size of the particles when rendering.
Velocity Multiplier – Controls the length of the motion blur when rendering.
Particle Visibility Lists Type – Specifies whether the list includes or excludes particles.
Sort Voxels -- Specifies if Alembic voxels are sorted by their names:
0 – Skips sorting.
1 – Performs sorting.
First Map Channel – Specifies how to remap the mapping channels:
-1 – No remapping.
0 – Remapped to channel 0.
1 – Remapped to channel 1.
Particle Render Mode – Controls how the particles in the proxy are rendered in the viewports. The available options are Point and Sphere.
Use Alembic Offset – When enabled, uses the alembic animation frame offset.
Velocity Color Set – Specifies an optional name for the color set where the velocity is written.
Instancing – Enables or disables the instancing of alembic duplicated objects.
Subdivide All Meshes – When enabled, subdivides alembic PolyMesh and SubD objects. When disabled, subdivides only SubD objects.
Subdiv Type – Specifies one of the following subdivision types:
0 – Catmull-Clark subdivision.
1 – Loop subdivision.
Subdivision Level – Specifies the number of subdivision levels.
Subdivide UVs – When enabled, subdivides mapping channels.
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 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 will be of greater detail than required by distance. Values greater than 1.0 mean that the resolution of the level will be smaller than the one determined by distance. A value of 0.0 means that no point cloud level will be loaded and the original mesh will be rendered instead.