Cooking this node can generate many USD time samples, rather than just a single time sample at the current time. This can be equivalent to having a Cache LOP following this node, but it will evaluate much faster, and does not cache data from any other nodes. This allows animated data to be authored to USD without introducing a node time dependency which would then cause all following nodes to also be time dependent. This can vastly improve playback performance of some LOP Networks.

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.

Our LED projectors are compatible with any C-mount lens, can project areas of various sizes, feature a vast range of interchangeable patterns and, in contrast with laser projectors, provide clearer edges and more uniform illumination (no speckle effect).

When turned on, forces a sample to be created at exactly the primary sample time. If the Samples value, together with the shutter open and close times, already place a sample at the primary sample time, turning on this option has no effect. Otherwise, this option causes an addition sample to be added. This means that the actual number of samples per primary sample may in fact be one more than the number specified in the Samples parameter.

Dome lightbulb

When the Sampling behavior is Sample frame range, this parameter controls the number and spacing of base time samples to be generated by this node. The default values of this parameter are @fstart, @fend, and @finc. These values correspond to the start, end, and step size of the global Houdini animation settings when interacting with Houdini. When using a ROP node to generate a range of frames, these values correspond to the start, end, and increment values specified on the ROP node being executed. This default ensures that a USD file written to disk will contain time samples for exactly the frame range requested by the ROP (regardless of the Houdini animation settings).

If you want to create a new cube primitive at /world/objects/cube1 on an empty stage: Set Primitive Specifier to “Define”, and the Parent Primitive Type to “Xform”.

In edit mode, the node has a Primitive pattern parameter. This lets you specify the prim(s) the node should operate on. You can click the select button beside the text box to select the primitives from the scene graph tree. You can also use primitive patterns for advanced matching, including matching all prims in a collection.

The Camera Prim parameter provides the scene graph path of a camera primitive from which the shutter open and close times are extracted to provide the offset values relative to the primary time sample.

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.

Dome LightBathroom

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

In 3D space, latitudes -pi/2 and +pi/2 correspond to the negative and positive y direction. Latitude 0, longitude 0 points into positive z direction; and latitude 0, longitude pi/2 points into positive x direction.

If you use a latitude-longitude map, you use should follow the OpenEXR specification for these kinds of environment maps. The following is from the OpenEXR documentation:

This version of the Dome Light LOP creates a USD prim with the DomeLight_1 schema, as opposed to earlier versions of this asset which create a USD prim with the older DomeLight schema.

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

In all sampling modes, if a parameter on this node does not vary with time, and does not rely on other time sampled data from the stage, only a single default value will be generated in USD for the corresponding attribute. USD time samples are only generated for parameters that may vary over time.

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

Opto Engineering offers a wide range of industrial LED illuminators, designed to illuminate uniformly with direct or indirect light, with diffused or collimated light, in various wavelengths and operating modes (continuous/strobed/boosted). We offer various illumination geometries including collimated telecentric illuminators, pattern projectors, backlights, ring light units, coaxial, dome, bar and spot illuminators.

This node belongs to a class of nodes that create or edit USD prims directly. These nodes operate in Create mode or Edit mode. This is controlled by a Create primitives checkbox or a Create/Edit popup menu. In create mode, the node creates new prims. In edit mode, the node changes the attributes on an existing prim. The Edit mode has two variations. Edit will not modify primitives which have a houdini:editable attribute set to false. Force edit will modify a primitive regardless of the existence or value of this attribute. This attribute can be set on a primitive using the Configure Primitives LOP.

When Shutter is set to Specify Manually, these two offset values are added to the primary sample time to indicate the shutter open and close times. The open time should be less than or equal to zero, and the close time should be greater than or equal to zero.

The environment is projected onto the image using polar coordinates (latitude and longitude). A pixel’s x coordinate corresponds to its longitude, and the y coordinate corresponds to its latitude. Pixel (dataWindow.min.x, dataWindow.min.y) has latitude +pi/2 and longitude +pi; pixel (dataWindow.max.x, dataWindow.max.y) has latitude -pi/2 and longitude -pi.

Dome LightLED

For example, instead of naming models after the node that created them, you might want to name them after the geometry inside, and organize them under a /Models branch.

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

Use this mode to make sure an attribute is only set on primitives of the correct type. For example, only UsdGeomSphere primitives are likely to have a radius attribute.

Opto Engineering machine vision illuminators are designed to satisfy the ever more stringent requirements of industrial automation.

Opto Engineering has also applied telecentric technology to its LED illuminators: our collimated illuminators, combined with our telecentric lenses, offer exceptional performance in optical measurement applications, with increased depth of field and minimal undesired reflections. Some of our illuminators are designed for use with our lenses, generating lighting optimized for specific fields of view and, in some models, also install directly to their compatible lenses.

Dome Lighttruck

A gamma (i.e., exponential) control over shadow strength with linear distance within the falloff zone (between Falloff and Distance.

Opto Engineering LED pattern projectors are designed for use in 3D reconstruction, profile measurement, stereo vision, alignment, flatness control and robot guidance for pick&place applications. Opto Engineering offers a complete range with various power ratings, operating modes (continuous/strobed) and wavelengths, as well as special models with a tilting mechanism that enables uniform projection even on inclined surfaces.

If the Specifier is Define or Over, this parameter will cause some ancestor primitives to be authored with a specifier of Class. This makes it easy to create an Over or Define within a Class without having to use two separate nodes. When the Specifier is Class, this parameter is disabled because the entire primitive hierarchy is already authored as Class primitives.

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

Authors an override of an existing prim. Attributes not explicitly authored on this prim will get their values from the existing prim on the lower layer.

The size of the data window should be 2*N by N pixels (width by height), where N can be any integer greater than 0.

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.

You will usually set the dome light to project a texture (environment map), such as a generic sky dome, or an IBL light probe (mirror-ball) reading taken on set.

Lighting is a crucial component of any machine vision system: choosing an illuminator of a given color or geometry can effectively reveal or mask the characteristics of an object, thus enabling the software to process the resulting image properly.

If you want to override the radius of a sphere at /world/objects/sphere1: Set Primitive Specifier to “Over”, and the Parent Primitive Type to None. This makes sure the primitive types of any existing ancestor prims are not be modified by this node.

The Start/End/Inc parameter is used to generate multiple times at which this node’s parameters are evaluated, and a USD time sample is created for each attribute at each one of these times.

If the input to this node is time dependent, this node behaves as if it is in Sample current frame mode. Otherwise it behaves as if it is in Sample frame range mode.

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.

The number of subframe samples to create for each primary sample. These samples are evenly distributed between the shutter open and close times. Note that such an even distribution may or may not create a sample at exactly the primary sample time.

Deletes the attribute input connection to its source. Input connections take precedence over attribute values, so disconnecting an input allows the attribute value to take effect.

Houdini 20.5 Nodes LOP nodes

Changes the state of all control menu parameters to Do Nothing, so that this node will not apply any changes. Also grabs the current values of each property from the first Primitives match, and sets the values of the corresponding parameters to match. This means that changing any parameter’s control menu to Set or Create mode will set the property to its current value, making it easier to apply changes to an existing value rather than setting a brand new value.

For each primary sample generated by this node, these parameters can cause additional samples to be generated around that primary sample time. This is most often used to ensure that accurate data exists at exactly the camera shutter open and close times, as well as at the primary sample time.

DomeLights in Car

In addition to that, any connectable USD attributes (i.e., the ones in the inputs: namespace) will have menu items that allow disconnecting them from their sources.

Parameters that correspond to a USD attribute have a pop-up menu to the left that controls how the node authors the attribute.

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.

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

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

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.

Makes the attribute appear to not exist, so it takes on its default value. (If the attribute doesn’t already exist on the prim, this does nothing.)

Dome lightfixture cover

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

A token which indicates the starting alignment of the dome light’s top pole. This alignment is for the dome itself and is not inherited by the namespace children of the dome.

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.

Dome LightCeiling

If any parents of a path in Primitive paths do not exist, this node will automatically create them. In this case, it will create parent nodes of this type.

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.

Dome lightTesla

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

Whether this node should create new prims, or edit existing prims. In addition, the Force Edit option can be chosen to cause this node to ignore the houdini:editable attribute on prims, and always edit the specified attributes. This is in contrast to the Edit mode which will trigger a warning and not set attributes on prims with the houdini:editable attribute set to false.

The maximum distance to check for objects shadowing this light. The default is -1, meaning no limit. Setting this may speed up rendering if you know all objects you want shadowed are within a certain distance.

The default is usually /$OS. This creates a primitive at the root level with the same name as the node (for example, /tube1). This is a useful default for preventing naming conflicts, but terrible for organization. You should try to remember to change the Primitive path to a better value when you create prims.

VAT IT02011230204 Fiscal code and registration number at Mantova Business Register 02011230204 Nr. REA: MN-216669 - Share Capital: 205.258,00 €

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

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.

When Shutter is set to Use Camera Prim, this is the scene graph path of a camera prim on the input node’s stage. The shutter open and close attribute values are read from this primitive.