Houdini 20.0 Nodes Geometry nodes

TOP Network geometry node

The TOP Network operator contains SOP nodes for running tasks.

Since 17.5


Cook Controls

Generate Static Work Items

Generates static work items in all nodes in the TOP network. None of the work items will be cooked, and dynamic nodes will do nothing.

Cook Output Node

Cooks the output node in the TOP network and any out-of-date nodes connected to it. If you want to recook all the nodes in the TOP network, click Dirty all first and then click this button.

Dirty All

Dirties all the work items in all of the TOP nodes inside the network and marks every node inside the network as needing to recook.

Cancel Cook

If any nodes in the TOP network are currently cooking, cancels their cook.


You can add cook controls for any TOP network to any node. For more information, see Adding TOP network cook controls to any node.

Save/Load Task Graph

Save Task Graph

Saves the state of all work items in the TOP network to an external file, which you can then restore with the Load Task Graph button. The task graph is saved to the path specified by the Task Graph File parameter.

Load Task Graph

Dirties the TOP network and loads the task graph file specified by the Task Graph File parameter.

Task Graph File

Specifies the path to the task graph cache file to save/load. This is used by Save Task Graph and Load Task Graph buttons, and it is where the network auto saves to when Auto-Save Rate is turned on.

Auto-Save Rate

When on, TOPs saves the task graph to disk at regular intervals. The save rate is specified in seconds. For example, the default rate of 10 saves the graph every 10 seconds. This can be useful when you want to checkpoint a large graph in its fully-cooked state.

Save Graph Attributes to .hip

When on, all the global attributes stored on the graph are saved to its .hip file. This makes it so that when you next open the .hip, the global attributes will still be available on the graph.

Work Items and Scheduling

Default TOP Scheduler

Specifies the default scheduler node that is used by all TOP nodes in the network, unless a TOP node has its own Scheduler override.

This can be a relative node path. As such, since your Schedulers are most likely at the main level of the network (and not inside a subnet), you can just use the Scheduler’s node name. For example, localscheduler or hqueuescheduler.

Default Item Label

When on, specifies the label that is assigned to any work item in the TOP network that was generated by a Processor with the Use Default Label setting.

On Node Recook

Determines what happens to work items when a node is recooked after it has been modified. By default, PDG will regenerate work items in the node, which updates their attribute values to match the parameters and invalidates existing output caches.

Update Work Items and Invalidate Caches

The default behavior. When a TOP node recooks, its work items are updated to match the parameters on the node. Work items that are modified in the process then have their output files invalidated.

Update Work Items Only

Attributes on work items are updated to match the parameters on the node, but the output cache files are not invalidated.

Ignore Changes

Nodes are not automatically recooked. Work items are left as-is unless the node is explicitly dirtied.

Evaluation Time

Determines what time value is used when evaluating parameters in the TOP network without an active work item. If a parameter is evaluated against a particular work item, the work item’s frame will determine the parameter’s evaluation time.

Network Cook Time

Parameters are evaluated using the time value that was set when the TOP network first began to cook. Changes to the current time while the network is cooking will not affect parameter evaluation.

Global Start Time

Parameters are evaluated using the global start frame/time value, regardless of the current evaluation time.


Parameters are evaluated at the custom time value specified by the Custom Time parameter.

Custom Time

Specifies the time value to use when evaluating parameters in the TOP network without an active work item.

This parameter is only available when Evaluation Time is set to Custom.

Save Scene File if Required

When this parameter is enabled, PDG will save the current .hip file before cooking if there are unsaved changes and work items in the graph use the scene file. Otherwise, if this parameter is disabled, the scene file will never be saved automatically.

A dialog will be displayed before the scene is saved, however the dialog also an option to make the selection the default use it for future cooks.

Geometry nodes