### Advanced NVIDIA Driver Options on Linux Source: https://docs.otoy.com/houdini/SoftwareRequirements.html Access advanced options for the NVIDIA driver installer on Linux. Consult the driver's installation files for specific commands and options. ```bash $ nvidia-installer --advanced-options ``` -------------------------------- ### Instance Color Parameters Source: https://docs.otoy.com/houdini/TextureInstanceColor.html Configuration parameters for the Instance Color texture node. ```APIDOC ## Instance Color Parameters ### Description The Instance Color texture node is used to distribute color (Cd) information across geometric instance IDs via an Attribute node such as Attribute Create or Attribute from Map. ### Parameters - **Power** (float) - Controls the image brightness. - **Color Space** (string) - Determines the color space of the image texture. - **Legacy Gamma** (float) - Controls the image's luminance; only used with Linear sRGB+Legacy Gamma color space. - **Invert** (boolean) - Inverts the image's color output values. - **Linear sRGB Invert** (boolean) - Swaps the order of gamma correction and image color conversion. - **Filename** (string) - The file path name of the image texture. - **Reload** (boolean) - Reloads the file if the file or preferences have changed. - **Image Chosen Layer Name** (string) - Indicates the chosen layer name if the image has multiple layers. - **IES Photometry Mode** (string) - Adjusts the normalization of data from an IES file. ``` -------------------------------- ### Uninstall NVIDIA Driver on Linux Source: https://docs.otoy.com/houdini/SoftwareRequirements.html Use this command to uninstall the current NVIDIA driver on Linux systems. Ensure you check the driver's installation files for specific uninstall instructions. ```bash $ sudo nvidia-installer --uninstall ``` -------------------------------- ### Spotlight Node Parameters Source: https://docs.otoy.com/houdini/Spotlight.html Configuration parameters for the Spotlight node in Octane for Houdini. ```APIDOC ## Spotlight Node Parameters ### Description The Spotlight node is used to place a spotlight-shaped texture onto the surface of an object. It is typically connected to the Efficiency input on a Black Body Emission node. ### Parameters - **Orientation** (enum) - Primary axis for the emission cone. - **Direction or Target** (vector/point) - Specifies the direction or target point; ignored if orientation is set to surface normal. - **Cone Angle** (float) - Width of the cone angle in degrees. - **Hardness** (float) - Controls how abruptly the emission pattern falls off at the edges. - **Normalize Power** (boolean) - Keeps the emitted power constant when the cone angle changes. ``` -------------------------------- ### Scatter on Surface Parameters Source: https://docs.otoy.com/houdini/ScatteronSurface.html Detailed explanation of parameters used for scattering objects on surfaces. ```APIDOC ## Scatter on Surface Parameters ### Description This section details the parameters used to control the scattering of objects on surfaces within Houdini. ### Parameters #### Object Selection Method - **Method** (string) - Required - The method for scattering the connected objects. Available options: Sequential, Random, and Selection Map. #### Object Selection Seed - **Seed** (integer) - Required - Seed value used to randomize the selection of source objects. #### Distribution on Surfaces - **Method** (string) - Required - The method used to distribute the instances on the scatter surface. - One Instance per Vertex: An instance is placed at each vertex. - One Instance per Edge: An instance is placed along the edges using the position and spacing values. - Evenly Spaced Instances on Edges: Instances are placed along edges with more random results. - One Instance per Polygon: Instances are placed at the center of each polygon. - Random Instances by Relative Area: Instances are placed randomly based on polygon size. - Random Instances by Relative Density: Instances are placed randomly using a texture map specified in the Relative Density Map parameter. - Disabled: No instances are placed on the surface. #### Distribution on Particles - **Enabled** (boolean) - Optional - Distributes instances on particles. #### Distribution on Hair - **Enabled** (boolean) - Optional - Allows for instances to be distributed along hair strands. - One Instance per Hair Vertex: An instance is placed at each vertex of each hair strand. - One Instance per Hair: Instances are placed on each hair strand using the specified position values. - Evenly Spaced Instances on Hair: Instances are placed along the hair strands using position and spacing values. - Disabled: No instances are placed on the hair strands. #### Position on Edge - **Value** (float) - Optional - When scattering on edges, defines the position of instances along the edge. #### Spacing on Edges - **Value** (float) - Optional - When scattering on edges, defines the spacing between instances along the edge. #### Poisson Disk Sampling - **Enabled** (boolean) - Optional - When randomly scattering on the surface by area or relative density, this option distributes instances to prevent them from being too close. #### Position on Hair - **Value** (float) - Optional - When scattering on hair strands, defines the position of the instances along the hair. #### Spacing on Hair - **Value** (float) - Optional - When scattering on hair strands, defines the spacing between instances. #### Seed - **Value** (integer) - Required - The global seed used to randomize instance placement. #### Instances - **Count** (integer) - Optional - When the Distribution Method is set to Surface Area or Relative Density, this parameter determines the total number of instances to scatter across the surface. #### Culling Min - **Threshold** (float) - Optional - All instances in areas of the map with a value below this threshold are removed. #### Culling Max - **Threshold** (float) - Optional - All instances in areas of the map with a value above this threshold are removed. #### Culling Angle Low - **Threshold** (float) - Optional - All instances on surfaces with a normal below this threshold in relation to the reference up vector are removed. #### Culling Angle High - **Threshold** (float) - Optional - All instances on surfaces with a normal above this threshold in relation to the reference up vector are removed. #### Smooth Normals - **Enabled** (boolean) - Optional - Determines whether smoothing should be applied across the surface of the instances. #### Normal Align - **Blend Factor** (float) - Optional - Blend factor between the reference up direction and the default normal of the instance. Values closer to 0 align the instance with the reference up direction, and values towards 1 align with the default normal. #### Front Align - **Blend Factor** (float) - Optional - Blend factor between the reference front direction and the default front of the instance. Values closer to 0 align the instance with the reference front direction, and values towards 1 align with the default front. #### Orientation Priority - **Priority** (string) - Optional - If the Up and Front Vector are not orthogonal, this parameter determines which one has priority. #### Up Direction Mode - **Mode** (string) - Optional - Selects between the use of a reference direction or a reference point. Reference point allows for finer control over the orientation. #### Reference Up Direction - **Vector** (Vector3) - Optional - When Up mode is set to Direction, the reference up vector will point in this direction. #### Reference Up Point - **Point** (Vector3) - Optional - When Up mode is set to Point, the reference up vector will point towards this location. #### Front Direction Mode - **Mode** (string) - Optional - Selects between the use of a reference direction or a reference point for the front direction of the scattered objects. #### Reference Front Direction - **Vector** (Vector3) - Optional - When Front mode is set to Direction, the reference front vector will point in this direction. #### Reference Front Point - **Point** (Vector3) - Optional - When Front mode is set to Point, the reference front vector will point towards this location. #### Rotation Mode - **Mode** (string) - Optional - Determines how the rotation parameters will affect the instanced geometry. #### Rotation Min - **Value** (float) - Optional - Specifies the minimum rotation value for the instances. #### Rotation Max - **Value** (float) - Optional - Specifies the maximum rotation value for the instances. #### Rotation Step - **Value** (float) - Optional - When the Rotation mode is set to Random or Map and this parameter is non-zero, the values will be aliased to the nearest step. #### Scale Mode - **Mode** (string) - Optional - Determines how the scale parameters will affect the instanced geometry. #### Scale Min - **Value** (float) - Optional - Specifies the minimum scale value for the instances. ``` -------------------------------- ### Analytic Light Parameters Source: https://docs.otoy.com/houdini/AnalyticLight.html This section details the parameters available for the Analytic Light in Octane for Houdini, categorized by their respective tabs. ```APIDOC ## Analytic Light ### Description The Analytic light offers a fast approximation of direct light from large direct light sources on diffuse or glossy materials. It estimates the complete contribution for every sample, considering the material's roughness and the light source's shape. Supported light types include Disk, Quad, Sphere, and Tube. ### Transform Tab Parameters - **Translate/Rotate/Scale**: Determine the position and orientation of the light source. - **Viewing/Look At/Path Options**: Constrain the light source via script, path, or another object. ### Light Tab Parameters - **On**: Turns the light source on or off. - **Enabled in Viewports**: Determines if the light source illuminates objects in the viewports. - **Light Types**: Selects the shape of the light source (Disk, Quad, Sphere, Tube). - **Shader Path**: Path to the shader used for the light. - **Object Layer ID**: Specifies a number for use with Layers to Render in the Octane ROP node. - **Object Layer Color**: Specifies a color for the Object Layer Color Info AOV. - **Object Baking Group**: Assigns the object to a baking group. - **General Visibility**: Controls the visibility of the object and its shadow. - **Camera Visibility**: Boolean to specify if the object is visible to the camera (enabled by default). - **Shadow Visibility**: Boolean to specify if the shadow cast by the object is visible to the camera (enabled by default). ### Emission Material Tab Parameters - **Diffuse**: Determines the surface color of the light source. - **Opacity**: Specifies the transparency of the light surface. - **Shadow Catcher**: Makes the entire lighting system a shadow catcher object. - **Light Color**: Determines the color of the light source. - **Surface Brightness**: If enabled, the surface area of the light source affects brightness. - **Double Sided**: Displays the lighting surface on both sides. - **Power**: The overall brightness of the light source. - **Sampling Rate**: Indicates how often the light source should be sampled. - **Light Pass ID**: ID for the light pass capturing emitter contribution. - **Visible on Diffuse**: Enables light source visibility on diffuse surfaces (enabled by default). - **Visible on Specular**: Enables light source visibility on specular surfaces (enabled by default). - **Cast Shadows**: Enables light sources to cast light and shadows on diffuse surfaces (enabled by default). - **Transparent Emission**: Light sources cast illumination on diffuse objects even if the light source is on a transparent material. ### Analytic Light Tab Parameters - **Analytic Light Type**: Determines the shape of the light source. - **Spread Angle**: Controls the spread angle of the light source. - **Spread Cutoff Hardness**: Hardens or softens the edge of the illumination. - **Normalize Power**: Keeps luminance constant when emission color/temperature changes (disabled by default). - **Falloff Radius**: Determines how far the illumination reaches from the light source origin. - **Use in Post Volume**: Enables or disables the light source in post volume rendering. - **Quad Width/Height**: Sets width and height for the Quad light type. - **Disk Width/Height**: Sets width and height for the Disk light type. - **Sphere Radius**: Sets the radius for the Sphere light type. - **Tube's Cap Radius & Length**: Sets the radius and length for the Tube light type. ``` -------------------------------- ### Volumetric Spotlight Parameters Source: https://docs.otoy.com/houdini/VolumetricSpotlight.html This section details the parameters available for the Spectron Volumetric Spotlight, categorized by their function. ```APIDOC ## Spectron Volumetric Spotlight Parameters ### Description The Spectron Volumetric Spotlight is an efficient lighting system for creating realistic light beams, fog volumes, and god rays by emitting light and interacting with volumetric mediums. ### Transform Tab Parameters These parameters control the position, orientation, and viewing options of the light source. - **Translate/Rotate/Scale** (Vector3) - Determines the position and orientation of the light source in the scene. - **Viewing/Look At/Path Options** (Various) - Parameters for constraining a light source via a script, a path, or another object. ### Light Tab Parameters These parameters control the general properties and visibility of the light source. - **On** (Boolean) - Turns the light source on or off. - **Enabled in Viewports** (Boolean) - Determines whether the light source illuminates objects in the viewports. - **Light Types** (Enum) - Determines the shape of the light source. - **Shader Path** (String) - The path to the shader used for the Spectron light. - **Object Layer ID** (Integer) - Specifies a number for the Layers to Render setting in the Octane ROP node. - **Object Layer Color** (Color) - Specifies a color for the Object Layer Color Info AOV. - **Object Baking Group** (Integer) - Specifies the baking group the object belongs to. - **General Visibility** (Float) - Controls the level of visibility for both the object and its shadow. - **Camera Visibility** (Boolean) - Specifies if the object is visible to the camera. Enabled by default. - **Shadow Visibility** (Boolean) - Specifies whether the shadow cast by the object is visible to the camera. Enabled by default. ### Spotlight Tab Parameters These parameters control the specific characteristics of the spotlight beam. - **Throw Distance** (Float) - Determines the volumetric distance of the light source. Larger values with narrower beams. - **Cone Width** (Float) - Sets the radius of the volumetric cone of illumination. - **Barn Doors** (Various) - Parameters to set the shape of the barn door effect. ### Scattering Tab Parameters These parameters control how light interacts with the volumetric medium. - **Density** (Float) - Increases the absorption density. - **Volume Step Percent** (Float) - Percentage of the voxel size for volume stepping. Decreasing this value decreases render speed. Default is 100%. - **Volume Shadow Ray Step Percent** (Float) - Step length used by the shadow ray for marching through volumes. - **Use Volume Step Length for Volume Shadow Ray Step Length** (Boolean) - Checkbox to use Volume Step Percent for Volume Shadow Ray Step Percent. - **Absorption** (Texture/Color) - Assigns a texture or color to determine the material's absorption value. 0 (black) means no absorption. - **Invert Absorption** (Boolean) - Inverts the absorption value. - **Scattering** (Texture/Float) - Determines how fast light scatters. A value of 0 disables scattering. Higher values scatter light faster. ``` -------------------------------- ### Instance Highlight Node Source: https://docs.otoy.com/houdini/InstanceHighlight.html The Instance Highlight node allows you to visually distinguish specific instances within your scene by assigning them unique highlight colors. ```APIDOC ## Instance Highlight Node ### Description This node is used to highlight a specific instance ID number by applying a distinct color. ### Parameters #### Instance Highlight Parameters - **Highlight Color** (Color) - The color to be applied to the specified instance ID. - **Regular Color** (Color) - The color for all other instances that are not highlighted. - **Instance ID** (Integer) - The ID number of the specific instance to highlight. - **Swap Colors** (Boolean) - If enabled, swaps the 'Highlight Color' and 'Regular Color' values. ``` -------------------------------- ### Medium Volume VOP Parameters Source: https://docs.otoy.com/houdini/MediumVolume.html Detailed explanation of each parameter available in the Medium Volume VOP node for configuring volumetric effects. ```APIDOC ## Medium Volume VOP Parameters ### Description This section details the parameters of the Medium Volume VOP node used for configuring volumetrics shading in Octane for Houdini. ### Parameters #### Volume Medium Parameters - **Density** (float) - Determines the density of particles in the volume. Affects absorption, scattering, and emission amplification. - **Volume Step %** (float) - Percentage of voxel size for volume stepping. Default is 100%. Decreasing improves accuracy but slows rendering. Increasing speeds up rendering but reduces accuracy. - **Volume Shadow Ray Step %** (float) - Step length used by shadow rays for marching through volumes. - **Ray Step Increase Factor** (float) - Determines the rate at which volume ray steps increase. - **Use Volume Step Length for Volume Shadow Ray Step Length** (boolean) - Checkbox to use the Volume Step Length for Volume Shadow Ray Step Length as well. - **Single Scatter Amount** (float) - Ratio of scatter events to direct light calculation in volumes. - **Displacement Pin** (texture/node) - Allows a texture to control volume sample position displacement. - **Volume Padding** (float) - Expands the volume bounding box by a given percentage in all six directions when displacement is used. - **Absorption** (color/float/texture) - Controls light absorption. Default is a 0-1 value slide (0=no absorption, 1=full absorption). Can be replaced by a color or texture. The color's value and saturation influence absorption. If 'Invert Absorption' is active, the behavior is reversed. - **Absorption Ramp Pin** (Volume Ramp) - Connect a Volume Ramp to define color and density range for absorption. Colors on the left map to less dense areas, colors on the right map to denser areas. These values are multiplied by the Absorption value. - **Invert Absorption** (boolean) - Inverts the absorption characteristics. If active, 0 (black) means full absorption and 1 (white) means no absorption. - **Scattering** (color/float/texture) - Controls how quickly light scatters through the surface. High values scatter sooner, low values scatter deeper. Default is a 0-1 value slide (0=no scattering, 1=full scattering). Can be replaced by a color or texture. - **Scattering Ramp Pin** (Volume Ramp) - Connect a Volume Ramp to define color and intensity range for scattering. Similar mapping to Absorption Ramp Pin. - **Phase Pin** (float) - Controls the direction of light scattering. 0 is even scattering, positive values are forward scattering, negative values are backward scattering. - **Emission Pin** (Blackbody/Texture) - Controls volume light emission using Blackbody or Texture emission maps. - **Emission Ramp Pin** (Volume Ramp) - Uses a Volume Ramp to alter the color of volume emission. Works best with a Texture Emission node. - **Compatibility Version** (enum) - Matches the Octane version's behavior. Options: Latest (2024.1) - Default, 2023.1. ```