In Atoms you can save your simulation on disk using Atoms caches, then it is possible to reuse these caches with the "cacheReader " behaviour moduleor with a Atoms Cache Actor. The Atoms Cache is lightweight and fast and it can increase the performance of your level.
You can also twwak tweak your caches with the cache reader module in combination with the Layout Tool or using other behaviour modules.
Exporting a cache
You can export a cache from within the points layout mode in the Modes panel.
You can add a slot for each agent group you want toe export in your cache and select an agent group.
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Please note, agent group might not appear in the combo box after selecting them. Please click on the "Refresh" button to refresh the groups on each combo box. |
There also few other options:
- Export path
- Start/End frame
- Skip frame Till Stating: if starting frame is greater than 1, all the frames before that won't be added to the cache
FPS: the interval used for caching frames.
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Please note, if you are planning to export caches from Unreal and use them later, it's worth noting they might not look as smooth as caches exported from Atoms Crowd supported apps. |
with the "Atoms Cache Exporter".
Before you can export a cache you have to set up a level sequence. Create one from the viewport menu.
Then open the sequence into the sequencer and drag and drop the agent groups you want to export.
Finally for each agent group add a new track for the "Static Frame" property:
Finally set two or more key frames making sure their value actually match the frame number they are on. Set the interpolation of all key frames to linear or the exported simulation won't look right.
Open the Atoms Cache Exporter via the Atoms Crowd Menu: Atoms Crowd > Cache Exporter
There are few options in the UI:
- Level sequence
- Export path
- Cache Start Frame: The simulation will start exporting only from this frame in the sequencer. The "Set Start Cache Frame" button will take the start frame of the sequencer range and set on the "Cache Start Frame" field
Start Sim Frame: The simulation won't start until this frame in the sequencer. The "Set Start Sim Frame" button will take the start frame of the sequencer range and set on the "Start Sim Frame" field
Once all the fields are set you can click export.
Cache Exporter
The cache exporter will export four files per frame:
- header: basic info such as number of agents at the current frame, number of created agents and number of deleted agents
- frame: agent data such as agent type, position, velocity, bbox and variation
- meta: agents metadata
- pose: agent skeleton data
To make the caches more portable, all the agent type files are saved in a subfolder next to your cache files. The cache will also have a file with no padding containing global infos, such as start frame, end frame, agent ids, etc.
Importing a cache
To import a cache from disk, create a new agent group and then attach a cacheReader module. Form the "cachePath" attribute you can set che cache pathjust drag and drop the file with no padding (i.e. mycache.atoms) inside the content browser. You can then assign the new Atoms Cache Asset to Cache Reader module or to an Atoms Cache Actor.
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Please note, the atoms cache exporter for Atoms Realtime does not export the meshes like the cache exporter for Atoms Crowd does. If you are planning to use these caches in Atoms Crowd supported apps, please make sure to have a valid agent type configuration with skeleton and meshes. |