Houdini 20.5 Nodes LOP nodes

Karma Texture Baker

Create a Render Settings primitive to create texture maps that define shading state for an object.

This node type is hidden. It is no longer supported.
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Since 20.5

Overview

The Karma Texture Baker LOP creates USD render var, render product and render settings primitives to set up texture baking for a single object. This node writes to the USD stage and configures rendering for Karma. You can then write the stage to disk or further modify it with LOP nodes.

Note

Baking currently only works for objects with a MtlX Standard Surface VOP shader.

Parameters

Common Settings

Rendersettings Primitive Path

Scene graph path to the RenderSettings prim to render with. If this is blank, the node looks for default render settings on the root prim. If the root prim has no render settings, the node will use default settings.

Baking Mode

Specifies how the shading point is determined for each point on the bake mesh.

  • Trace. This mode sends rays from the low res mesh in the direction of the surface normal to find the shading point. This method works if multiple objects are baked onto a single mesh. The other scene objects don’t need UV coordinates.

  • UV Match. This method takes a single high-res mesh and determines the shading point by matching UV coordinates from the low-res mesh. UV Match makes sense if the high-res mesh doesn’t align very well to the low res mesh.

Bake Mesh

This is the mesh that will be baked. The polygons are rasterized based on the mesh’s UV coordinates.

Cage Mesh

This parameter is only available when you set Baking Mode to Trace. Sometimes it’s problematic to determine the direction to trace rays from the bake mesh to the scene. When you specify a cage mesh, rays are sent from the position on the cage mesh through the matching position on the bake mesh. This leads to finer control when determining the shading position.

High Res Mesh

This parameter is only available when you set Baking Mode to UV Mesh and specifies the high-res mesh that has matching UV coordinates. The position data of this mesh are used to compute the shading information.

Dicing Camera

Specifies the camera that’s used for dicing subdivision or displaced surfaces. This parameter is mandatory for the texture baker to work correctly.

Output Picture

The filename of the output image. When you bake a single image, the node uses the name exactly as entered here.

However, when you render separate images for each AOV, this name will be the starting point for the individual AOV filename. The AOV name will be appended to the Output Picture just before the file extension. The file extension will be changed to the format that you've chosen from the Image Format dropdown on the Images tab.

Resolution

The horizontal and vertical size of the output image, in pixels.

UDIM

When baking, Karma will render the images for a single UDIM tile. The parameter specifies which UDIM tile will be rendered.

Images

Create Separate Files

Renders either a single image with multiple AOVS, or store each AOV in a separate file.

Tip

To see all AOVs, render a single image to MPlay.

Image Format

Specifies the format the image format of the separately rendered AOV. The file extension will change accordingly.

Name Separator

This character will be used to separate the file name from the Output Picture parameter and the AOV channel name. For example, when you bake Nt and P AOVs and Output Picture is render/bake.png, the output file names will be render/bake_Nt.png and render/bake_P.png.

Note

You can inspect the stage and see details for all the render products in the created render settings primitive.

Expand UV Islands

Post-processes the images by smearing the boundaries of the UV islands into the empty areas of the image. This will produce better results when MIP-mapping the textures. This process can be time-consuming. For faster iterations, only turn on this feature for the final baking.

Outputs

This tab specifies AOVs that are defined as outputs of the shading state.

Tangent Space Normal (Nt)

Creates an AOV for the tangent space normal. You can change the AOV’s default Nt name.

Displacement (Ds)

Displacement between the bake mesh and the shading point as a scalar value. You can change the AOV’s default Ds name.

Vector Displacement (Vd)

Displacement between the bake mesh and the shading point as a vector value. You can change the AOV’s default Vd name.

Tangent-Space Vector Displacement (Vdt)

Displacement between the bake mesh and the shading point as a tangent-space vector value. You can change the AOV’s default Vdt name.

Occlusion (Oc)

Ambient occlusion. You can change the AOV’s default Oc name.

Cavity (Cv)

The occlusion along the inverted normal at the shading position. This produces “relief” shading. You can change the AOV’s default Cv name.

Thickness (Th)

The thickness at the shading position. You can change the AOV’s default Th name.

Curvature (Cu)

The curvature at the shading position. You can change the AOV’s default Cu name.

Alpha (Af)

The alpha at the shading position. You can change the AOV’s default Af name.

Shading Position (P)

The shading position. You can change the AOV’s default P name.

Shading Space

When you store the P AOV, this is how the position should be represented

  • World Space. The shading position is written directly to the AOV.

  • Bake Mesh Bounding Box. The shading position is fit to the bounding box of the bake mesh.

  • Scene Bounding Box. The shading position is fit to the bounding box of the whole scene.

  • User Defined. The shading position is fit to user specified values.

Shading Normal (N)

The shading normal. You can change the AOV’s default N name.

Shading Position (Ng)

The geometric shading normal. You can change the AOV’s default Ng name.

Shader Values

This folder specifies AOVs that are defined by the MtlX Standard Surface shader’s inputs. Currently, you can only use inputs to a single MtlX Standard Surface shader, so blending of shaders is not supported.

Additional AOVs are available for all defined inputs of the MtlX Standard Surface.

Base Combined

The MtlX Standard Surface defines the base color as base * base_color, where base is a scalar multiplier on the color given by base_color. This AOV stores the multiplied result as a single channel.

The Coat Normal, Shading Normal and Shading Tangent values are stored exactly as they are wired into the shader (in world position).

Lighting

When you bake textures, lighting computations are not always required. However, Karma is capable of baking lighting AOVs.

Enable Lighting

Turns on lighting computations for baking.

Beauty

Stores the beauty image as an AOV with RGBA colors through the LPE C.*[LO]

Combined Diffuse

Stores the direct and indirect diffuse illumination through the LPE C<RD>.*L.

Direct Diffuse

Stores the direct diffuse illumination through the LPE C<RD>L.

Indirect Diffuse

Stores the indirect diffuse illumination through the LPE C<RD>.+L.

Facing Ratio

Stores the facing ratio from the Dicing Camera.

Extra AOVs

Define any custom AOVs here. In addition to lighting AOVs, you can also specify AOVs defined by Primvars or other Karma-specific AOVs.

Baking

This folder contains parameters that control the baking operations.

Make Bake Mesh Invisible

In most cases, the bake mesh should be invisible to any rays. This means that the mesh won’t contribute to occlusion or other ray-traced effects. However, there might be situations where the the bake mesh remains visible.

Bake Traceset

Define the visible traceset of primitives on the bake mesh. You can use tracesets to subdivide a mesh into different parts. For example, the clothing on a character might have tracesets like pants, shirt and jacket. You can then define which part/traceset you want to bake. You can specify tracesets on the object through the Custom Tracesets parameter on the Render Geometry Settings LOP.

  • With the default * entry, all tracesets will be visible.

  • If the bake mesh has a string primvar named bake_traceset, the values in the primvar will override this setting. Note that this traceset also affects secondary rays (occlusion, curvature, etc.)

  • You can also define a blank-separated list of different tracesets to combine them, e.g. pants shirt.

Primary Samples

Specifies the number of camera rays sent for each pixel. Higher values improve the quality of the rendering.

Trace Bias

When rays are sent from the bake mesh to the scene, this bias is used to offset a ray’s origin from the surface of the bake mesh. You can use this parameter to arbitrarily offset the bake mesh along its normal without having to define a cage mesh.

Use MikkT Tangents

MikkT is a common standard for tangent space used in baking tools to produce normal maps.

Dicing Quality

When baking displaced meshes or subdivision surfaces, this parameter can control the level of detail of the dicing.

True Displacement

Sometimes, displacement shading inverts the surface and produces bad normals. This parameter lets you run displacement shaders as bump map shaders. Alternatively, you can disable displacement shading entirely.

Occlusion Samples

Determines the number of indirect rays used when computing Occlusion. If the resulting AOV is noisy, you can increase Occlusion Samples without having to increase the Primary Samples.

Occlusion Max Distance

The maximum distance to consider when computing Occlusion. A small distance can speed up occlusion shading at the cost of accuracy.

Occlusion Ray Bias

Controls the ray bias when computing Occlusion.

Thickness Samples

Determines the number of indirect rays used when computing Thickness. If the resulting AOV is noisy, you can increase Thickness Samples without having to increase the Primary Samples.

Cavity Samples

Determines the number of indirect rays used when computing Cavity. If the resulting AOV is noisy, you can increase Cavity Samples without having to increase the Primary Samples.

Curvature Samples

Determines the number of indirect rays used when computing Curvature. If the resulting AOV is noisy, you can increase Curvature Samples without having to increase the Primary Samples.

See also

LOP nodes

  • Add Variant

    Adds one or more variants to a variant set on a primitive. This node creates the primitive if it doesn’t exist.

  • Additional Render Vars

    Create multiple render vars.

  • Asset Reference

    Reference, Transform, and select variants of a USD Asset.

  • Assign Material

    Assigns a material to one or more USD primitives. You can use also programmatically assign materials using VEX, programmatically override material settings for each assignment, and programmatically assign materials to geometry subsets.

  • Assign Prototypes

    Switch point instances or USD instanceable prims to instance a different prototype.

  • Attribute VOP

    Create/edit USD attribute values using a VOP network.

  • Attribute Wrangle

    Create/edit USD primitive attributes using a VEX snippet.

  • Auto Select LOD

    Automatically selects a level-of-detail variant based on the primitive’s distance from the camera.

  • Background Plate

    Sets up hold-out or matte objects that leave holes in the scene through which the background is visible. These prims still take shadows and contribute to reflections as if they were the background.

  • Bake Skinning

    Bakes animation driven by a UsdSkel into transforms and point positions.

  • Basis Curves

    Creates or edits a basis curves shape primitive.

  • Begin Context Options Block

    This node begins a block of LOP nodes, within which certain context options have certain values.

  • Blend

    Partially applies edits to a layer’s attributes based on a fractional weight.

  • Blend Constraint

    Blends transforms according to a list of weights specified as parameters.

  • Cache

    Caches the results of cooking the network at different times, increasing playback speed.

  • Camera

    Adds a USD camera to the scene.

  • Capsule

    Creates or edits a capsule (tube with hemispherical ends) shape primitive.

  • Collection

    Creates/edits collections using primitive patterns.

  • Component Geometry

    Geometry container or import source, in a network created by the Component Builder tool.

  • Component Geometry Variants

    Sets up geometry variants, in a network created by the Component Builder tool.

  • Component Material

    Assigns materials to geometry in a network created by the Component Builder tool.

  • Component Output

    Assembles the final Component prim, in a network created by the Component Builder tool.

  • Cone

    Creates or edits a cone shape primitive.

  • Configure Layer

    Edits metadata on a layer.

  • Configure Primitives

    Edits various metadata on one or more primitives.

  • Configure Properties

    Configures metadata on properties (relationships and attributes).

  • Configure Stage

    Configures metadata for how to load layers into the stage and asset resolution.

  • Coordinate System

    Define named coordinate systems used in shaders.

  • Copy Property

    Copy properties from one primitive to another, or renames properties on a primitive.

  • Create LOD

    Uses the PolyReduce SOP to automatically generate multiple levels of detail from a high-res model, and stores them as USD variants.

  • Cube

    Creates or edits a cube shape primitive.

  • Cylinder

    Creates or edits a cylinder shape primitive.

  • Distant Light

    Creates or edits a USD Distant Light, representing a far-off light source such as the sun. Adds some useful Karma-specific attributes.

  • Dome Light

    Creates or edits a USD Dome Light prim. A dome light emits light inward, simulating light coming from the sky/environment surrounding the scene.

  • Draw Mode

    Sets draw mode properties on USD model assets.

  • Drop

    Runs a simulation to drop primitives under gravity.

  • Duplicate

    Creates copies of a prim (and its descendants).

  • Edit

    Interactively transforms prims in the viewer. Can use physics collisions to position props realistically.

  • Edit Context Options

  • Edit Material

    Allows you to edit an existing USD material by modifying parameters and shader connections. This can be useful if the existing material is on a non-editable layer.

  • Edit Material Properties

    Lets you build a spare parameter interface that reflects material or shader input attributes to directly edit their values.

  • Edit Properties

    Lets you build a spare parameter interface to directly edit attribute and relationship values.

  • Edit Properties From Node

    Lets you refer to the parameter on another node to directly edit attribute and relationship values.

  • Edit Prototypes

    Modify the prototypes of native or point instances in-place, without disturbing the instancing setup.

  • Edit Target Layer

    Allows you to apply edits directly in a lower layer, instead of overriding prims and attributes in the active layer.

  • Error

    Generates a message, warning, or error, which can show up on a parent asset.

  • Explore Variants

    Visualize, set, or extract variants on primitives.

  • Extract Instances

    Converts (heroes) an instance into a real editable prim.

  • Fetch

    Grabs the output of another LOP, potentially in another LOP network.

  • File Cache

    Caches (writes out once and then reads from) USD layers (possibly animated) to disk.

  • Follow Path Constraint

    Constrains a prim to follow a path curve.

  • For Each

    The end node of a For-Each loop block.

  • Geometry Clip Sequence

  • Geometry Color

    Adds display color and display opacity primvars to geometry.

  • Geometry Sequence

    Imports a sequence of geometry files into LOPs as animated geometry.

  • Geometry Subset VOP

    Creates USD geometry subsets within geometry prims (similar to groups in SOPs) based on evaluating a VEXpression or VOP network.

  • Graft Branches

    Takes prims/branches from the second input and attaches them onto branches of the scene graph tree in the first input.

  • Graft Stages

    Takes scene graph trees from other inputs and attaches them onto branches of the scene graph tree in the first input.

  • HDA Dynamic Payload

    Cooks a OBJ or SOP asset on disk and imports the animated geometry output as a USD payload.

  • Hermite Curves

    Creates or edits a hermite curves shape primitive.

  • Houdini Feather Procedural

    Generates feathers for rendering.

  • Houdini Preview Procedurals

    Invokes Houdini Procedurals while working interactively.

  • Houdini Procedural: Crowd

    Houdini Crowd Procedural for Solaris.

  • Houdini Procedural: Hair

    Houdini Hair Procedural for Solaris.

  • Houdini Procedural: Ocean

    Houdini Ocean Procedural for Solaris.

  • Houdini Procedural: RBD

    Houdini RBD Procedural for Solaris.

  • Inline USD

    Parses usda code representing a layer and adds it to the layer stack.

  • Insertion Point

    Represents a point in the node graph where nodes can be inserted.

  • Instancer

    Instances or copies primitives onto points.

  • Isolate Scene

    Work in masked areas of the stage.

  • Karma

    Renders the USD scene using Houdini’s Karma renderer.

  • Karma Cryptomatte

    Setup Cryptomatte AOVs for Karma.

  • Karma Fog Box

    Creates a constant volume within a box.

  • Karma Physical Sky

    Creates a Karma Sky Dome and Sun Light rig.

  • Karma Render Products

    Create multiple render products sharing common settings.

  • Karma Render Properties

    Configure Render Properties for Karma.

  • Karma Sky Atmosphere

    Creates or edits a Karma Sky Atmosphere.

  • Karma Sky Dome Light

    Creates or edits a Karma Sky Dome Light.

  • Karma Standard Render Vars

    Create standard karma render vars (AOVs/Image Planes).

  • LPE Tag

    Manage Lights' LPE Tags.

  • Labs Karma AOVs for RenderMan Denoiser

    Generates AOVs for the Pixar RenderMan denoiser.

  • Layer Break

    Starts a new active sublayer that subsequent nodes will edit, and indicates all previous layers will be discarded when saving to disk.

  • Layer Replace

    Replaces all uses of a certain layer with a substitute layer from its second input.

  • Layout

    Provides tools for populating a scene with instanced USD assets. You can place individual components, paint/scatter components in different ways using customizable brushes, and edit existing instances.

  • Light

    Creates or edits a USD Light prim. This node also adds some useful Karma-specific attributes.

  • Light Filter Library

    Authors USD light filter primitives from VOP nodes.

  • Light Linker

    Creates USD light link properties based on rules.

  • Light Mixer

    Lets you interactively edit USD properties for multiple lights.

  • Load Layer for Editing

  • Loft Payload Info

    Adds basic information from inside a payload to the primitive that loads the payload.

  • Look At Constraint

    Constrains a prim to always point toward a target.

  • Mask from Bounds

    Sets a primvar based on whether/by how much selected prims are inside a bounding shape.

  • Match Size

    Resizes and recenters the input geometry to match a reference bounding box.

  • Material Library

    Authors USD material primitives from shader VOP nodes.

  • Material Linker

    Creates material assignments based on rules.

  • Material Variation

    Creates attributes/primvars to override material parameters per-prim/instance.

  • Merge LOP

    Merges the layers from incoming stages into a unified layer stack.

  • Merge Point Instancers

    Merges point instancers into a single consolidated point instancer.

  • Mesh

    Creates or edits a mesh shape primitive.

  • Modify Paths

    Modify asset path attribute values.

  • Modify Point Instances

    Modifies point transforms and property values for individual point instances.

  • Motion Blur

    Adds time samples to allow motion blur when rendering.

  • Null

    This node does nothing. It can be useful to insert a Null into a network as a fixed point in the network that you can refer to by name in expressions/scripts.

  • Output

    Represents the output of a subnetwork. Allows you to design a node asset with multiple outputs.

  • Parent Constraint

    Makes a primitive appear to inherit the transform hierarchy of another prim somewhere else in the tree.

  • Points

    Creates or edits a Points shape primitive.

  • Points Constraint

    Position and Orient primitives using point positions from a geometry.

  • Primitive

    Bulk-creates one or more attributes of a certain type.

  • Prune

    Hides or deactivates primitives and point instances.

  • Python Script

    Lets you write Python code in the node to use the USD API to directly manipulate the stage.

  • RBD Destruction

    An example for a fracturing simulation in USD, also useful as a canned effect.

  • Reference

    References the contents of a external USD files and/or layers created by other LOP nodes into a branch of the existing scene graph tree. Can also remove or replace existing references.

  • Render Geometry Settings

    Applies renderer-specific geometry settings to geometry in the scene graph.

  • Render Product

    Creates or edits a UsdRenderProduct prim, which represents an output of a renderer (such as a rendered image file or other file-like artifact produced by a renderer), with attributes configuring how to generate the product.

  • Render Settings

    Creates or edits a UsdRenderSettings prim, which holds the general settings for rendering the scene.

  • Render Var

    Specifies a custom variable computed by the renderer and/or shaders, either a shader output or a light path expression (LPE).

  • Resample Transforms

    Generates interpolated transform time samples from existing time samples on USD prims.

  • Restructure Scene Graph

    This node has various operations for editing prim paths, variant sets, and composition arcs.

  • Retime Instances

    Offsets and/or scales the timing of animation on selected instances.

  • SOP Character Import

    Imports a character or animation from a SOP network into the USD scene graph.

  • SOP Create

    Lets you create geometry in a SOP subnetwork inside this node, so you can create geometry in-place in the LOP network instead of needing a separate SOP network.

  • SOP Crowd Import

    Imports a crowd from a SOP network into the USD scene graph.

  • SOP Import

    Imports geometry from a SOP network into the USD scene graph.

  • SOP Modify

    Converts USD geometry into SOP geometry, runs the SOP subnet inside this node on the geometry, and converts the changes back to USD overrides.

  • Scene Doctor

    Validates primitives on a USD stage.

  • Scene Import

    Imports models, materials, and lights from the Object level into the LOP network.

  • Scope

    Creates a scope primitive. Scope is the simplest form of grouping, and does not have a transform. Scopes can be useful for organizing the scene tree.

  • Set Extents

    Sets the bounding box metadata of selected primitives.

  • Set Variant

    Selects (switches to) one of the variants stored in a variant set on a primitive.

  • Simulation Proxy

    Generates low-poly collison geometry suitable for physical simulation and creates a proxy relationship to the original model.

  • Sphere

    Creates or edits a sphere shape primitive.

  • Split Point Instancers

    Splits a point instancer into two or more instances, which divide up the original instances.

  • Split Primitive

    Splits USD geometry prims into child primitives based on geometry subsets or primvar values.

  • Split Scene

    This node splits a scene graph into two disjoint sets of primitives.

  • Stage Manager

    Provides a convenient interface to reference in many files at once and place them in the scene graph tree.

  • Store Parameter Values

    Lets you store temporary (unsaved) data in the stage.

  • Sublayer

    Imports from USD files or other LOP node chains into as sublayers, or removes/replaces/reorders existing sublayers.

  • Subnet

    Encapsulates a LOP subnetwork, allowing you to organize and hide parts of the network.

  • Surface Constraint

    Constrain a prim to stick to a surface.

  • Switch

    Passes through one of several inputs, based on a parameter choice or expression.

  • TimeShift

    Outputs the stage as it is at a different point in the timeline.

  • Transform

    Edits the transforms of selected USD primitives.

  • Transform UV

    Moves, rotates, and scales texture coordinates on USD primitives.

  • USD ROP

  • USD Render ROP

  • Unassign Material

    Unbinds a material from one or more USD primitives.

  • Value Clip

  • Vary Material Assignment

    Assign different materials across a number of prims to create variation.

  • Volume

    References volume data on disk into a volume prim containing field prims.

  • Xform

    Creates or edits an Xform prim. Xform (and its sub-classes) represents a transform in the scene tree.