Houdini 20.5 Nodes Geometry nodes

Whitewater Post-Process geometry node

Prepares the whitewater simulation for rendering.

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Overview

This node allows you to transform the output of the Whitewater Solver after the simulation. More specifically, redefining the pscale and density attributes is possible based on other attributes such as age, depth and distance to the container. You can also flatten the edges of the simulation to smoothly transition outside of the region of interest area. This node can output the modified particles, a fog volume along with a velocity field, or a mesh representation of the whitewater simulation which can be rendered as a uniform volume.

For more information, see the SOP Whitewater page.

Inputs

Whitewater Simulation

The particle simulation from the Whitewater Solver.

Container

The container geometry from the Whitewater Solver as a surface field or geometry hull.

Collisions

All collision objects from the Whitewater Solver as surface and velocity fields.

Outputs

Whitewater

The whitewater representation chosen for rendering (particles, volume, or mesh).

Parameters

Output

The desired output from this node.

Particles

A modified particle representation of the whitewater simulation.

Fog Volume

A fog volume representation of the whitewater simulation with velocity field.

Mesh

A mesh representation of the whitewater simulation with transferred velocity.

Display Particles as Spheres

Render the particle as spheres in the viewport.

Set Alpha Equal to Density

Set the alpha attribute to the normalized density.

Voxel Size

The size of voxels in the generated VDB. Points smaller than this will not be correctly resolved by the VDB and can lead to visual artifacts.

Vel Voxel Size Multiplier

A multiplier of the Voxel Size applied to the voxel size of the velocity (vel) field only.

Add Gradient Field

Compute a gradient field to be used as surface normals to render specular highlights.

Write 16-Bit Floats

A flag to specify that all volumes (density, vel, and gradient) will be down-converted to 16 bits when written to disk. This does not affect how they are stored in memory.

Close Hole Scale

Amount of voxels to move the surface out and then in. This operation will close small holes in the surface by connecting nearby particles to the same blob.

Smoothing Iterations

Number of times to repeat the smoothing operation.

Meshing Adaptivity

How closely to match the surface when converting to polygons. Higher adaptivity will allow more variation in polygon size, using fewer polygons to express the surface.

Density

Set Density Attribute

Replace the density attribute using the user-specified attributes below.

Density Range

Remap the (0,1) density range to new min and max values.

From Age

Set Density by Age

Scale the density using the age attribute.

Age Range

Define the range of age values to be remapped to the (0,1) range.

Age Ramp

Remap the transition of the Age Range using a custom curve.

From Normalized Age

Set Density by Normalized Age

Scale the density using the normalized age attribute.

Normalized Age Range

Define the range of normalized age values to be remapped to the (0,1) range.

Normalized Age Ramp

Remap the transition of the Normalized Age Range using a custom curve.

From Depth

Set Density by Depth

Scale the density using the depth attribute.

Depth Range

Define the range of depth values to be remapped to the (0,1) range.

Depth Ramp

Remap the transition of the Depth Range using a custom curve.

From Domain

Set Density by Proximity to Domain Boundaries

Scale the density using the proximity to the domain.

Distance Range

Define the range of distance values to be remapped to the (0,1) range.

Distance Ramp

Remap the transition of the Distance Range using a custom curve.

Particle Scale

Set Particle Scale Attribute

Replace the particle scale attribute using the user-specified attributes below.

Particle Scale Range

Remap the (0,1) particle scale’s range to new min and max values.

From Age

Set Particle Scale by Age

Scale the particle scale using the age attribute.

Age Range

Define the range of age values to be remapped to the (0,1) range.

Age Ramp

Remap the transition of the Age Range using a custom curve.

From Normalized Age

Set Particle Scale by Normalized Age

Scale the particle scale using the normalized age attribute.

Normalized Age Range

Define the range of normalized age values to be remapped to the (0,1) range.

Normalized Age Ramp

Remap the transition of the Normalized Age Range using a custom curve.

From Depth

Set Particle Scale by Depth

Scale the particle scale using the depth attribute.

Depth Range

Define the range of depth values to be remapped to the (0,1) range.

Depth Ramp

Remap the transition of the Depth Range using a custom curve.

From Domain

Set Particle Scale by Proximity to Domain Boundaries

Scale the particle scale using the proximity to the domain.

Distance Range

Define the range of distance values to be remapped to the (0,1) range.

Distance Ramp

Remap the transition of the Distance Range using a custom curve.

Domain

Size

The size of the bounding box to use for container clipping and whitewater flattening.

Center

The position of the bounding box to use for container clipping and whitewater flattening.

Clip Container Against Bounding Box

Enable container clipping against the bounding box.

Flatten outside Bounding Box

Flatten outside Bounding Box

Flatten the whitewater particles to the water level offset by their depth attribute.

Output Flattened Attribute

Output the flatten attribute used to drive the flattening of the whitewater particles.

Suppress Near Collisions

Disable flattening inside colliders.

Collision Bandwidth

Multiplier on the whitewater scale to activate the Suppress Near Collisions. Any particles this close or closer to a collider will not be flattened.

Plane

The orientation of the plane for flattening.

XY Plane

The plane defined by the x and y axis.

YZ Plane

The plane defined by the y and z axis.

ZX Plane

The plane defined by the z and x axis.

Shape

The 2D shape to use as a mask to apply flattening.

Rectangle

A rectangle on the user-defined plane extending to infinity both above and below the plane.

Circle

A circle on the user-defined plane extending to infinity both above and below the plane.

Water Level

Defined the water level to flatten the particles to.

Flatten Distance

A distance going inside of the mask to allow a smooth transition into flattening.

See also

Geometry nodes