Houdini 22.0 Nodes Copernicus nodes

Pyro Block Begin Copernicus node

Start of a Pyro simulation block.

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Since 21.0

Note

Although COP Pyro is in COPs, you need DOP level permissions to use it. This means that COP Pyro is not available in Houdini Core, but only in Houdini FX, Houdini Apprentice, Houdini Indie, and Houdini Education.

This node marks the beginning of a Pyro simulation block.

Operations that are independent of previous frames should occur before the block so they only get cooked once. Likewise, post-processing operations that are not needed for feedback should occur after the block end.

The passthrough input can be used to bring additional inputs inside the block, and feedback can be used to add additional values that need to be updated every frame.

Pyro Configure COP can be used to set up the initial VDBs for a simulation.

Note

In Copernicus blocks, you can’t use Time Shifts when they require the inputs of the block to cook at different times. As a workaround, Time Pack the required frames before the Block Begin and wire them into the block as a cable. Each iteration of the block extracts only the required wire from the cable.

Parameters

Block Path

The path to the Pyro Block End COP, which is the final and closing node of this block. The Block End node must be at the same network level as this Block Begin node.

Inputs

vdb_ref

VDB metadata to set the voxel size of the simulation.

density

A Float VDB providing how thick the smoke is at a voxel.

Use the Source tab on Pyro Block End to control how this volume is mixed into the simulation.

temperature

A Float VDB providing the temperature at each voxel.

Note that newly activated voxels will get a temperature of 0, so that value should usually be used as a baseline.

Use the Source tab on Pyro Block End to control how this volume is mixed into the simulation.

v

A Vector VDB providing the wind speed of each voxel. Note that this does not include any Ambient Velocity.

Use the Source tab on Pyro Block End to control how this volume is mixed into the simulation.

flame

A Float VDB of the current voxel flames.

Use the Source tab on Pyro Block End to control how this volume is mixed into the simulation.

divergence

An optional Float VDB providing a goal divergence for the velocity, allowing the fluid to expand or contract.

Use the Source tab on Pyro Block End to control how this volume is mixed into the simulation.

collision

An optional Float VDB providing a signed distance field (SDF) of a collider. Negative voxels will act like colliders.

collisionv

An optional Vector VDB providing a velocity for the collision objects. These are in world space, so they will be internally adjusted by Ambient Velocity.

feedback

A cable providing wires that will be fed back to the next iteration of the solve. It is important that the input’s cable structure exactly matches the Pyro Block End COP’s input.

This is only read on the initial frame. Any feedback field can be resized and advected alongside the simulation.

passthrough

Optional cable providing layers and VDBs that should be computed outside of the simulation. They are read each frame, so can be used to inject animated sources, but cannot depend on the results of the simulation.

bounds_geo

Optional Geometry input. This is read each frame, and controls the maximum extend of the simulation domain.

source_points

Optional Geometry input for sourcing from implicit surfaces using Pyro Source Shape.

collision_points

Optional Geometry input to set up collision from implicit surfaces using Pyro Collision Shape.

Outputs

density

A Float VDB of the density that has been fed back to this frame.

temperature

A Float VDB of the temperature that has been fed back to this frame.

v

A Vector VDB of the velocity that has been fed back to this frame.

flame

A Float VDB of the flame that has been fed back to this frame.

divergence

A Float VDB of the divergence that has been fed back to this frame.

collision

A Vector VDB providing a velocity of the collision objects to this frame.

feedback

A Cable of the extra data that has been fed back to this frame.

passthrough

A Cable passing through the input, updated every frame from the input.

See also

Copernicus nodes