Atoms supports Renderman, Arnold and Vray renderers. Atoms is shipped with a procedural for each renderer which can be used inside Maya/Houdini or standalone.
Maya
You can directly render agent groups, just launch a render and they will be automatically replaced with a procedural by the renderer.
In general, you should always export a cache of your simulation and then replace your agent groups with AtomsProxy nodes reading those caches.
Please be aware motion blur will not work if you render directly from an agent group. Motion Blur only works with AtomsProxy nodes.
VRay only works with Atoms Proxy nodes. It is not possible to render directly from agent group nodes.
Houdini
To render your simulation in Houdini, you must export an atoms cache and the create a Renderman/Arnold procedural node from the Atoms menu. AtomsProxy are available but they do not work as in Maya.
Variations
To create agent variations please check the next section