Caching agents - Houdini

In Atoms you can save your simulation on disk using the Atoms cache, then it is possible to reuse these caches with the "cacheReader" behaviour module. The Atoms Cache is lightweight and fast. It can increase the performances of your scene dramatically compared to using live simulation.

With the cache reader and the agents layout tool you can edit and tweak your cache.

Exporting a cache

You can open the cache exporter GUI using the shelf button or via the Atoms Menu: Atoms > Export > Cache Exporter

Open

• Create an agent group

• Add a grid layout behaviour module and set the size attribute to (5,1,5)

• Add a state machine behaviour module and set the state attribute to 1

• Create some other agent groups and move them

• Open the cache exporter form the Atoms menu: Atoms > Export > Cache Exporter

• Select the agent groups you have created from the list, then choose a path where your cache will be saved.

• Finally select your start and end frame.

• Click on the "Export" button.

Importing a cache

You can import a cache in a scene using the cacheReader behaviour module

• Create and agent group.

• Add a cacheReader behaviour module.

• in the cachePath attribute of the cache reader module pick the cache file (the file named youCacheName.atoms)

• Rewind the scene and atoms will load the cache. It also automatically load all the agent types that are missing from your scene.

• You can create multiple agent group to load different caches or the same cache multiple times. You can also move then around and rotate them.

Editing a cache

When a cache is loaded in your scene you can still edit it to change your layout or simulation.

Apply a new height field

Even if you exported the cache from some agent groups on a height field you can apply a new height field to your cache

• Create a new height field

• Create an agent group and import your cache using the cacheReader behaviour module

• In the height field attribute of the cache reader module set the new height field name you created

• Rewind the scene or press UpdateSim from the shelf and press play

Move agents

• Create an agent group and import your cache using the cacheReader behaviour module

• To move agents you can use the transitionOffset attribute or you can use the Agents Layout Tool

• Select the agent group and activate the agents layout tool from the Atoms menu: Atoms → Tools → Agents Layout Tool or just press enter

• Press Q to switch to the selection mode or press

  from the agent layout tool ui (press P to show the ui)

• Select the agents you want move

• Press A to switch to the move mode or press 

  from the ui

• Use the manipulator to move the agents where you want

• Rewind the scene or press UpdateSim from the shelf and press play

Rotate agents

• Create an agent group and import your cache using the cacheReader behaviour module

• To rotate agents you can use the rotationOffset attribute or you can use the Agents Layout Tool

• Select the agent group and activate the agents layout tool from the Atoms menu: Atoms → Tools → Agents Layout Tool

• Press Q to switch to the selection mode or press

  from the agent layout tool ui (press P to show the ui)

• Select the agents you want rotate

• Press Z to switch to the rotate mode or press 

  from the ui

• Press the LMB and move the mouse on the left or on the right to rotate the agents or press SHIFT+LMB to rotate around the group pivot

• Rewind the scene or press UpdateSim from the shelf and press play