TYPE: ROP
TITLE: Mantra ROP

This output operator is used to drive the mantra rendering program.

Parameters:
    Render               - Begins the render.

Standard Tab:
    Camera               - Which camera to render the scene from.
    Visible Objects      - Pattern defining objects which will be rendered.
    Contributing Lights  - Pattern defining lights which illuminate the scene.
    Unload SOPs          - Unload SOP geometry after used by the render
    Output Picture       - The picture or device to be rendered
    Image Format         - Which file format the image should be created with.
    Start/End/Inc        - Specifies the first & last frames and the possibly
                           fractional increment.
    Initialize Sim. SOPs - Force all simulation SOPs to be reset.
    Generate Script File - Outputs an .ifd file instead of piping the script
                           to mantra.
    Binary Script File   - Toggles between ascii and binary file formats.
    Script File          - Filename of the .ifd file.
    Render Command       - The command used to invoke the renderer.  Can be
                           modified with the popup window.
    Render in Background - Continue to use Houdini while rendering
    Super Sample         - Controls quality of anti-aliasing.
    Decouple Ray Sample  - Specify an alternate sampling rate for ray tracing.
    Resolution           - Override camera resolution with values specified.
    Pixel Aspect         - Override camera pixel aspect ratio.
    Fields               - Control for rendering video fields.
    Motion Blur          - The default motion blur for rendering.
                           This can be overridden by an individual object.
    Depth of Field       - Turn on rendering of depth of field effects.
    Jitter               - Limits the amount of jitter.  0 = no jitter.
    Dither               - Controls the amount of dithering performed.
    Gamma                - Gamma correction factor used.

Specific Tab:
    Generate Photon Map  - Instead of rendering the image, mantra will
                           generate a photon map.
     Photon Count        - Total number of photons to send into the scene.
     Global Photon Map   - File to store the global photons in.
     Caustic Photon Map  - File to store the caustic photons in.
    Irradiance Caching   - Cache irradiance/ambient-occlusion samples.
     Default Error       - Error required before new irradiance samples
                           will be computed.
     Default Sample      - If the shader calling irradiance() or occlusion()
                           does not specify a sampling, this value
                           will be used.
     Cache File          - File used for storing irradiance samples
     Cache Mode          - Reading the cache file will load up
                           existing samples into mantra.  If writing
                           is turned on, the irradiance values will be
                           written to the file at the conclusion of
                           the render.
                           WARNING:  This should not be used with
                           network rendering.

    White Point          - An overall scale applied to color after filtering.
    Filter               - Pixel filtering controls.
    Shadow Maps          - Controls which lights will auto-generate z-maps.
    Reflect Maps         - Controls which objects will generate reflection maps.
    Opacity Limit        - Allows speedups for scenes with transparency.
    Polygon Optimization - Faster or higher quality polygon rendering.
    Null Surface         - Optimize shadow map generation with null shaders.
    Transforms           - Combined transforms give better precision,
                           but in some cases, it's useful to separate
                           the camera transforms.
    VEX Profiling        - Print statistics on shading computations.
    SHOP References      - Controls output of SHOPs which might be
                           referenced by indirect geometry attributes.

                           Hardening SHOP references will cause the
                           shader strings associated with the SHOP to
                           be evaluated and stored with the geometry.
                           If the SHOP references variables like $OBJ,
                           this may be required.

                           Choosing "Indirect geometry..." will only
                           output SHOP shaders for SHOPs which are
                           referenced by indirect references on
                           geometry which is being rendered.

                           Declare all SHOPs will forcibly output all
                           SHOPs in the scene to the IFD.

                           Choosing to bypass all SHOP declarations
                           will leave geometry indirect references
                           un-referenced in the IFD.  This allows you
                           to "include" a file containing SHOP
                           declarations (this requires some knowledge
                           of the IFD structure).

                           NOTE:  Point attribute indirect references
                           are handled differently and are not
                           considered when de-referencing indirect
                           SHOPs.

    Scan Geometry        - Any objects which render disk file geometry
                           will have the disk files loaded and scanned
                           for indirect SHOP attributes.  This means
                           that Houdini must load the geometry into
                           memory for the purpose of this scanning
                           (which may cause memory and performance
                           issues when generating IFDs).

Deep Raster Tab:
    Aux Files            - Controls for rendering deep rasters.
      Variable Name      - The name of the global variable (or export
                           parameter) to be written out.
      Variable Type      - The VEX type of the variable.
      File/Plane Name    - The name of the output image (or plane when
                           rendering to a Houdini .pic file).
      Bit Depth          - The data type to be written to the output
      File Format        - When rendering to a non-Houdini format
                           picture, this specifies the format of the
                           output image.
      Enable Filtering   - Control for the filtering/blending of the
                           variable when mantra deals with edges.

    - If rendering to a Houdini .pic file, all deep raster images will
      be embedded in a single image.  The plane name for the deep
      raster will be used to name the color plane.

    - If mantra warns about "Variable <variable_name> not found", this
      usually indicates that the data type for a global variable isn't
      correctly specified.  It may also be printed out if shaders do
      not have the parameter specified as an "export" parameter.

Scripts Tab:
    Pre-Render Script    - Execute this script before any rendering.
    Pre-Frame Script     - Execute this script before each frame.
    Post-Frame Script    - Execute this script after each frame.
    Post-Render Script   - Execute this script after all rendering.

Local Variables:
    N        - The current frame of the range specified.  This always
               starts at 1.
    NRENDER  - Total number of frames being rendered.

See also: RenderMan(rman), mental ray(mental)
