Method

Field Level Sets use the same field structure as the Field Root Node – but instead of containing densities (“ink”), they contain an isosurface (distance field): each cell stores the distance to the surface. This means that while fields are typically used to model gas and smoke, level sets are an efficient way of modelling liquid simulation.

Field Level Sets can be used as procedurals via the Procedural Level Set node, allowing them to be rendered as meshes with the Procedural Meshing node.

Advecting and affecting the level set can cause it to lose accuracy and volume. Two mechanisms exist to improve this. Firstly, the “Renormalise Iterations” parameter controls a number of iterative renormalisation steps which improves the accuracy of the level set after being moved.
Secondly, in the case that the field is used to model a body of liquid in a container, the Floor Height and Floor Blend parameters control blending of a flat level of liquid into the level set each frame as a workaround to keep it from losing volume.

Setting the “Up-Res Distance Field” parameter will run the level set data at twice the width, height and depth of the velocity buffer. This typically allows for a more detailed visual result for the simulation, but without as great an increase in memory usage and impact on frame rate as running the whole field at twice the width, height and depth.

Transform

Name Description
Position X Move its position along the x-axis in local space.
Position Y Move its position along the y-axis in local space.
Position Z Move its position along the z-axis in local space.
Rotation Heading Rotate the object about the x-axis.
Rotation Pitch Rotate the object about the y-axis.
Rotation Bank Rotate the object about the z-axis.
Scale X Scale along the x-axis.
Scale Y Scale along the y-axis.
Scale Z Scale along the z-axis.

Inherit Transform Channels

Toggle which transform channels should be inherited. By default, all are on.

Attributes

Name Description
Width Pixel resolution of the field horizontally.
Height Pixel resolution of the field vertically.
Depth Changes how much resolution the depth of the field has.
Velocity Dampening How fast the velocities are dampened. Higher number = greater dampening
Lock Update Rate Locks the update rate of the field to a particular frame rate.
Locked Update Framerate Set the frame rate at which the field simulation is updated. Only functions with “Lock Update Rate” enabled.
Wrap Update At Edges Allow ink and velocities to wrap around from the edges. i.e. velocities at the right edge can push through to left.
Clear Every Frame Clears the ink and velocities of the field every frame. This means affectors will no longer function if connected to this node.
Visualise Field Generates an optical flow image, and renders it to the veiwport.
Renormalise Iterations The number of renormalisation steps to apply to the level set after it has moved.
Up-Res Distance Field Causes the field’s level set to be twice the width, height and depth of its velocity data.
Floor Height Controls the height of the “floor” plane in the field.
Floor Blend Controls the amount that the “floor” plane is re-injected into the field.
Gravity Add a gravity simulation to the level set animation.

Inputs

Name Description Typical Node Input
Bounding Box Bounding box beyond which fields are killed. Bounding Box
Transform Modifier Links all transform properties to the input node. Null
Target Node Always faces the x-axis towards the inputs anchor point. Null

Outputs

The outputs section for this node is currently being worked on.