Houdini 18.0 Nodes TOP nodes

Partition by Frame TOP node

Partitions work items based on their frame

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Partitions work items based on their frame and the selected frame rounding mode.

You can use this node to combine multiple subframes into a single frame unit, or to separate frames from different wedge variations. This allows you to run a simulation with integer frames that is internally loading source geometry at subframes.

For example, you can use this node to help with the following:

Parameters

Use Dynamic Partitioning

When on, the partitioner waits for all input work items to be generated before partitioning them. If the input work items are dynamic, then the partitioner has to wait for and depends on the parent(s) of those items.

Merge Input Attributes

When on, the partitioner merges the attributes of the work items in each partition and exports them to the partition itself.

Frame

Frame Rounding

When partitioning work items with fractional frames, determines how the frame is converted to an integer for partitioning.

Round Down

Rounds the frame value down to the nearest integer. For example, values from 1.0 to 1.9 are treated as frame 1.

Round Up

Rounds the frame value up to the nearest integer. For example, values from 1.1 to 2.0 are treated as frame 2.

Round Nearest

Rounds the frame value to the nearest frame. For example, values from 1.0 to 1.49 are treated as frame 1.0, and values from 1.5 to 2.0 are treated as frame 2.

Split by Attribute

When on, work items are split into separate groups before the items are partitioned. This parameter specifies the name of the attribute on the input work items that is used to determine those groups.

For example, you can set this parameter to wedgeindex in order to keep wedge variations in different partitions.

The following extra steps are performed when using a split attribute

  • The node looks up the value of the split attribute for each input work item.

  • The work items are then grouped based on their split attribute value. One group is created for each unique value of the split attribute.

  • The regular partitioning process is applied to each group of work items. Work items in different groups are always be in different partitions. Groups are processed in ascending order of their split attribute value.

Missing Attribute

Determines how the node should handle an input work item that does not have the split attribute.

This parameter is only available when Split by Attribute is on.

Ignore Work Item

Input work items that are missing the split attribute are not added to any of the partitions.

Add to Partitions with Matching Frame

Input work items that are missing the split attribute are added to partitions that have the same frame as the work item.

Add to All Partitions

Input work items that are missing the split attribute are added to all partitions produced by the node.

Use Frame for Partition Index

When on, the partitions that are created have their indexes set to the frame number assigned to the partition. When off, the partitions have their indexes set from 0 up to the number of partitions created.

When Wedge Attribute is also on, and you want to split frames by wedge index, it isn’t always possible to set the partition index to the frame number. That is because there may be different wedge variations with the same frame number. In this case, the node maintains a unique index for each partition, but the indexing begins at the first frame in the first wedge instead of at 0.

Ignore Items With No Frame

When on, work items with no frame value are ignored. Otherwise, an error is produced when you try to partition a work item that does not have a specified frame value.

Advanced

These are advanced parameters that give you a finer level of control over the behavior of the partitioner.

Auto Remove Stale Dependencies

When on, the partitioner removes old dependencies when recooking the node if the partitioning scheme changes as a result of the cook.

Force Re-Evaluation on Cook

When on, forces the partitioner to re-evaluate the partitioning scheme even if all of the work items are already cooked and no new work items have been added.

Dirtying Mode

Determines when a partition is dirtied and the effects on child items when that occurs. This is particularity useful for working around some of the limitations of using dynamic partitioning.

Standard

A given partition is dirtied when any of the work items in the partition are dirtied. In the case of dynamic partitioning, if any ancestor of a dynamic work item in a partition is dirtied, then all partitions are dirtied.

When a partition is dirtied, all of its children are deleted.

Non-destructive

The same dirtying behavior as Standard, except when a partition is dirtied, its children are dirtied instead of deleted.

Mapping Standard

A given partition is only dirtied if an item in the partition is dirtied or if the partition’s contents change as a result of a recook. When the partition is dirtied, any child work items are deleted.

Mapping Non-destructive

The same dirtying behavior as Mapping Standard, except when a partition is dirtied, its children are dirtied instead of deleted.

Sort Contents By

Determines the order that work items are sorted in when accessing the partitions on this node. This also affects the sort order of output files on the partition.

None

No sorting is applied. The work items in the partition are handled in no particular order.

Work Item Index

Work items in the partition are sorted based on their index.

Input Node Order

Work items in the partition are sorted based on the order of input nodes wired into this node. If two work items are from the same input, they are then sorted by index.

Attribute

Work items in the partition are sorted based on the attribute specified in the Sort Attribute field parameter.

Sort Direction

Determines whether the work items in this node’s partitions are sorted in ascending or descending order.

Sort Attribute

Specifies the name of the attribute to sort by.

This parameter is only available when Sort Contents By is set to Attribute.

Partition When

Determines when the partitioning step is performed on the input work items.

This parameter is only available when Use Dynamic Partitioning is on.

Input Items Are Generated

Inputs are partitioned once all of them have been generated.

Input Items Are Cooked

Inputs are partitioned once all of them are cooked. This is required when the partitioning scheme is based on the results of the work items' execution.

This makes this partitioner behave like a Wait for All node except that it may create multiple partitions.

Partition Target

Specifies the target TOP node for the partition. The partition scheme is applied to the work items in the target TOP node instead of this node’s input work items. The target TOP node must be a processor in the same graph above this node, and there cannot be any other mappers or partitioners between this node and the target.

This parameter is only available when Use Dynamic Partitioning is on.

Examples

example_top_partitionbyframe Example for Partition by Frame TOP node

This example demonstrates how to use the partition by frame node in PDG/TOPs.

See also

TOP nodes