Houdini 18.0 Nodes TOP nodes

Partition by Tile TOP node

Partitions work items spatially using axis-aligned bounding boxes.

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This partitions work items based on tiles so that each partition corresponds to a tile that contains work items with geometry that intersects with that tile. The tiles are arranged in a 3D grid, with origin at Tile Origin, where each axis has Tile Count number of tiles. Each tile has size per side calculated as Total Size / Tile Count. Tiles can be visualized as a grid of bounding boxes.

The source geometry is specified by attributes on each work item. The types of attribute data supported are points from string, points from vector, and bounding box. Points can be connected (i.e. a curve) or disconnected (point cloud), and points can be given a radius for size (i.e. sphere or tube).

Note that partitions are only created for tiles that contain or intersect with work item geometry. The resulting index of the partition corresponds to the tile index.

As an example, a Tile Count of 2×2×2 and a Total Size of 512 produces 8 axis-aligned bounding boxes, where each box is of size 256×256×256.

Parameters

Use Dynamic Partitioning

When this toggle is enabled the partitioner will wait for all input work items to be generated before partitioning them. If the input work items are dynamic, this means the partitioner will have to wait for and depend on the parent(s) of those items.

Merge Input Attributes

When this toggle is enabled the partitioner will merge the attributes of the work items in each partition and export them to the partition itself.

Tiles

Tile Origin

The offset of all tiles from world origin.

Tile Count

The number of tiles for each axis.

Total Size

The combined size of all tiles. To get a tile side’s size, the Total Size is divided by the Tile Count for that axis.

Tile Index Order

Specifies whether to use row-major or column-major for the tile indexing.

Write Tile Attributes

If enabled, writes out the tile origin, total tile size, tile count, intersecting tile’s position, intersecting tile’s minimum bounds, and intersecting tile’s maximum bounds. This can be useful for visualization.

Source

The source geometry is specified by attributes on work items.

Attribute Type

The type of attribute for the source geometry.

Points String: Points are specified as a string attribute. Similar to the Coordinates parameter in curve

Points Vector: Points are specifed as a position vector. An example is the P attribute for position.

Bounding Box: The source geometry is a bounding box with min and max bounds.

Points Attribute

Specifies the name of the points attribute.

Points Connected

Specifies whether the points are connected (e.g. curve) or disconnected.

Point Radius

Specifies the radius of each point for intersection test.

Min Bounds Attribute

The name of the attribute for the minimum bounds.

Max Bounds Attribute

The name of the attribute for the maximum bounds.

Advanced

These are advanced parameters that provide finer control over the behavior of the partitioner.

Auto Remove Stale Dependencies

When recooking the node, indicates that the partitioner should remove old dependencies if the partitioning scheme changes as a result of the cook.

Force Re-Evaluation on Cook

Forces the partitioner to re-evaluation the partitioning scheme even if all of the work items are already cooked and no new work items have been added.

Sort Contents By

Determines the order that work items are sorted 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 inputs nodes wired into the partitioner itself. 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 parameter.

Dirtying Mode

The dirty mode parameter offers fine grained control over when a partition is dirtied and the effects on child items when that occurs. This parameter is particularity useful for working around some of the limitation of using dynamic partitioning.

Standard

A given partition will be 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 will be 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 will be dirtied instead of deleted.

Mapping Standard

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

Mapping Non-destructive

The same as Mapping Standard, except when a partition is dirtied its children will be dirtied instead of deleted.

Partition When

This parameter is only enabled when using dynamic partitioning. It controls when the partitioning step is performed on the input work items.

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 except that it may create multiple partitions.

Partition Target

This parameter is only enabled when using dynamic partitioning. When the target is set, the partition scheme will be applied to the work items in the target TOP node instead of the 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 partitioner between this node and the target.

Examples

example_top_partitionbytile Example for Partition by Tile TOP node

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

See also

TOP nodes