Houdini 18.0 Nodes TOP nodes

Invoke TOP node

Invokes a compiled block on input geometry

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This node can be used to run a SOP compiled block on input geometry. The geometry can either be from the output files of an upstream work item or a custom file path, or native Houdini geometry stored in attribute by the Geometry Import TOP node.

When generating from partition, the invoke can optionally expand the partition items into separate inputs to the compiled block. For example, if the invoke is configured to run a compiled block with 3 inputs the data for those inputs can be loaded from a partition with at least 3 work items. If an incoming partition has fewer than 3 work items, a warning will be issued and the invoke procedure will not be applied for that partition.

TOP Attributes

numpoints

integer

The number of points in the output geometry. This attribute is added when the work item is cooked.

numprimitives

integer

The number of primitives in the output geometry. This attribute is added when the work item is cooked.

numvertices

integer

The number of vertices in the output geometry. This attribute is added when the work item is cooked.

sourceindex

integer array

The indices of the upstream items that were used as inputs to the Invoke operation. sourceindex[0] is the first input to the compiled block, sourceindex[1] is the second input, and so on.

Parameters

Work Item Generation

Whether this node generates static or dynamic work items. You should generally leave this set to "Automatic" unless you know the node’s work items can be computed statically, or that they need to be generated dynamically.

Dynamic

This node always creates dynamic work items: it waits until the upstream work items are known, and generates new work items from the upstream work items.

Static

This node always creates static work items: it creates the number of work items it thinks it needs based on the parameters (and any upstream static items) before the network runs.

Automatic

If the input is static (a static processor, or a partitioner with only static inputs, or a mapper), this node generates static work items, otherwise it generates dynamic work items.

Compiled Block

Block Path

The path to the compiled block end node.

Evaluation Time

When this parameter is enabled it overrides the time used when evaluating the block. By default, the compiled block will be evaluated at the frame value specified on the work item, or at time=0 if no frame is set.

Input Geometry

Expand Partitions

When this parameter is enabled, the invoke will expand upstream partitions and use the work items in those partitions when preparing the input geometry for the compiled block. The partition will need to have at least Input Count number of work items or a warning will be issued and no work will be done. If the partition has additional items in it, the data on the extra items won’t be passed to the compiled block.

Load During Cook

When this parameter is enabled, input geometry data will be loaded during the cook instead of when the invoke work items are generated. This is useful when the input data is produced at runtime by an upstream process, to avoid needing to make the Invoke node Dynamic.

Input Count

The number of inputs passed to the compiled block. Must be at least one in order to execute the compiled block.

Geometry Source

The source for the input data. Can be an output file or geometry attribute on an upstream work item or a custom file path.

Upstream File

The geometry for this input will be loaded from an output on the upstream work item, as specified by the File Tag parameter.

Upstream Geometry Data

The geometry for this input will be loaded from a geometry attribute on the upstream work item, as specified by the Attribute Name parameter

Custom File

The geometry will be loaded from the custom file path specified in the File Path parameter.

File Tag

When Geometry Source is set to Upstream File, this parameter specifies which file tag to use when selecting a file on the upstream work item.

File Path

When the Geometry Source is set to Custom File, this parameter specifies which geometry file to load.

Attribute Name

When Geometry Source is set to Upstream Geometry Datta, this parameter specifies which attribute on the upstream work item to load the geometry from.

Block Input Name

The name of the input as specified on the corresponding compiled block begin node.

Output

Write Geometry to

Determines whether output geometry should be written to a geometry attribute, a file on disk, or both.

Attribute

Output geometry should only be written to an attribute on the work item.

File

Output geometry should only be written to disk.

Both

Output geometry is written to both an attribute and to disk.

None

Output geometry is not stored, but numpoints, numvertices and numprimitives attributes are still set to the appropriate values.

Output Attribute

If Write Geometry to is set to Attribute or Both, the value of this parameter determines the name of the attribute to store output geometry to.

Output File Path

The path to write the resulting geometry, if Write Output to is set to File or Both.

Output File Tag

The tag associated with the output geometry file, if Write Output to is set to File or Both.

Examples

example_top_invoke Example for Invoke TOP node

This example demonstrates how to run compiled blocks using pdg data as input.

See also

TOP nodes