Houdini 20.0 Nodes TOP nodes

Range Extend TOP node

Extend the frame range of upstream work items and adds new work items as necessary

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Since 18.5

You can use this node to extend the frame range of the upstream work items. For example, if you have a ROP Geometry node that cooks a simulation from frames 1 to 100, you can use this node to extend the range to frames 1 to 120. The last 20 work items of the new frame range will depend on the frame 100 work item from the initial frame range.

You can also use this node to shift the frame range by a constant factor using the Pre Shift and Post Shift parameters.

By default the output file from frame 100 will also be copied onto the new frames 101 through 120. By setting the Copy Outputs For parameter you can instead choose to have no output files copied into the new frames.


This node requires that the input work items have a frame value and range attribute, so that TOPs can tell where a given work item lies within a larger frame range. The name of the range attribute is specified using the Range Attribute parameter. Other nodes that generate work items over a frame range will add set the range as an attribute to the work items, for example the Range Generate or ROP Fetch nodes.

Additionally, this node requires access to the full list of input work items in order to function correctly. If the node is dynamic, i.e. Generate When is set to Each Upstream Item is Cooked, then work item indices may not be unique or contiguous.


The $HH/help/files/pdg_examples/top_multishot example shows how you can use this node to shift and extend frame range data.

TOP Attributes




Generate When

Determines when this node will generate work items. You should generally leave this set to “Automatic” unless you know the node requires a specific generation mode, or that the work items need to be generated dynamically.

All Upstream Items are Generated

This node will generate work items once all of the input nodes have generated their work items.

All Upstream Items are Cooked

This node will generate work items once all of the input nodes have cooked their work items.

Each Upstream Item is Cooked

This node will generate work items each time a work item in an input node is cooked.


The generation mode is selected based on the generation mode of the input nodes. If any of the input nodes are generating work items when their inputs cook, this node will be set to Each Upstream Item is Cooked. Otherwise, it will be set to All Upstream Items are Generated.

Extend Values Of

Determines if the node should extend the frame range of input work items or if the values should be stored in a custom attribute.

Attribute Name

If Extend Values Of is set to Custom Attribute this parameter specifies the attribute name.

Range Attribute

The name of the attribute that determines the overall range start, stop and step values on the upstream items. TOPs needs to know this information so it can tell where a given work item falls within its frame range. Nodes like the Range Generate and ROP Fetch will write a range attribute onto work items automatically.

Update Range Attribute

When this parameter is enabled the range attribute specified using the Range Attribute parameter will have its value updated to match the new extended frame range.

Specify Range Using

Determines how the new range of values should be specified.


When Specify Range Using is set to Custom Range this parameter determines the new range of values.

Start/End Offset

When Specify Range Using is set to Start/End Offset this values in this parameter are used to extend the upstream frame range by a fixed amount. Rather than directly specifying a new range the values of this parameter are used to offset the existing frame range.

The new range will be: [upstream_start - start_offset, upstream_end + start_end, upstream_step].

Pre Shift

Frame values on upstream work items will be shifted by this value, before the frame range is extended.

Post Shift

Frame values on the work items in this node will be offset by the value of this parameter, after extending the frame range, creating the work items and adding dependencies on upstream items.

Copy Output Files

Determines which work items should have output files copied onto them from the upstream items.


RangeExtend Example for Range Extend TOP node

This example files demonstrates how the Range Extend TOP node can be used to extend a list of frame-based work items to a larger frame range.

See also

TOP nodes