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Domain, Solver Mode and Initial State

Configure Dense or Sparse simulation, voxel resolution, domain behavior, initial state and looping.

Lists and Nodes

In Lists, use Core Settings and the Cache tab for the controls on this page. In Nodes, Pyro Domain contains Solver, domain geometry, Voxel Size, Fire and Color channels, and other core defaults. Connect it before Pyro Dynamics. To configure boundaries, an initial state or looping in the graph, add Pyro Boundaries, Pyro Initial State or Pyro Looping between them. Use at most one active stage of each type. An omitted stage uses the Domain's stored defaults.

Solver Mode, Domain & Voxel Size

The permanently visible Core Settings block contains the solver mode, domain geometry, Voxel Size, Dense or Sparse Volume Budget, viewport mode, and solver playback controls.

Below Core Settings, use the two category rows to switch between Emitters, Colliders, Effects, Physics, Quality, Cache, and Viewport. Only the selected category is displayed, while Core Settings remains accessible.

Mode Best for Main tradeoff
Fast Dense look development, controlled boxes, quick dense smoke and fire uses a fixed box, so the whole box costs memory
Sparse Advanced larger scenes, expanding smoke, adaptive volumes, high-control setups more complex and depends on the active sparse memory limit

Core Simulation Controls

  • Solver: chooses between Fast Dense and Sparse Advanced.
  • Viewport: selects the active preview mode. Detailed display controls are in the Viewport tab.
  • Start Solver: starts simulation for the current scene.
  • Stop Solver: stops the running solver without removing the setup.
  • Reset: clears the current simulation state and starts again from the first frame or the selected initial state.
  • Step Frame: advances the simulation by one frame for controlled testing.
  • Live Update: updates the simulation when you scrub or change settings.
  • Catch Up Timeline Jumps: simulates missing frames after a timeline jump to preserve causal continuity. GPU Preview refreshes automatically when catch-up finishes. Disable it for fast navigation in long timelines; Pro Pyro then evaluates only the requested frame instead of replaying the skipped range.

Fast Dense Domain

  • Domain Box: the wireframe box that defines the Fast Dense simulation area.
  • Create / Select Box: creates the domain box or selects the existing one.
  • Voxel Size: controls the size of each simulation cell. Smaller values give more detail and much higher memory cost.
  • Domain Size: the size of the Fast Dense box in Blender units.
  • Dense Volume Budget: shows the resulting voxel resolution and estimated total voxel count.

Sparse Advanced Domain

  • Voxel Size: controls sparse simulation detail. Smaller values create more detail and use more memory.
  • Memory Limit: limits the number of active simulation cells and their GPU memory use. Raise it for larger volumes; lower it if the solver runs out of memory. The Add-on Preference Default Max Sparse Cells supplies the starting value for new Pyro setups.
  • Sparse Volume Budget: shows the configured Memory Limit and active sparse usage while the solver runs.

Initial State and Looping

Initial states and loop generation are grouped at the top of the Cache tab. They help you start from an existing volume or create loopable smoke or fire sequences from baked VDB data.

Initial State

  • Use Initial State: starts each reset from a saved VDB state instead of an empty domain.
  • VDB File: selects the VDB file used as the starting state.
  • Set Current Frame as Initial State: writes the current solver state to a VDB file and uses it as the new start state. If the selected file already exists and was not saved by this scene, choose a different file. Other files in the same folder are unaffected.
  • Delete Initial State: removes a VDB file saved by this scene when it is still unchanged. For another selected VDB file, it clears the reference and keeps the file.

In Nodes, configure these controls on Pyro Initial State and connect that stage into the Domain-to-Dynamics chain. A relative VDB path still requires a saved .blend file.

Looping

  • Enable Looping / Make Loop: enables loop generation from a baked VDB sequence.
  • First Frame: first frame of the final loop range.
  • Last Frame: last frame of the final loop range.
  • Blend Duration: number of frames blended from the end of the simulation back into the beginning.
  • Generate Loop Sequence: rebuilds the looped VDB sequence.
  • Clear Loop Sequence: removes the generated loop sequence.

In Nodes, set the range and generation controls on Pyro Looping and connect it between Domain and Dynamics. Its settings are separate from the Looping settings in Lists.