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Change fluid behavior at the container boundaries
Modifying fluids
Convert fluids to polygons
Define an arbitrary falloff region for fluid containers
If you don’t want the fluid to appear in part
of the volume, you can specify a falloff region by painting it or
using a curve in a container. It will give a softer edge than collisions
and won’t have any buildup of density in the area. To further soften
the edge, you can adjust the Edge Dropoff.
The falloff could be useful anywhere you need to control the shape
of a simulation, as long as the simulation itself doesn't look too
different. For example, if you want to guarantee that a cloud stays
contained within a certain shape, you can paint a falloff. You could
also use falloff to define a rough shape for an explosion or to
control the path of a mist.
In the following images, the letter “R” is made
using Fluid Effects and then it fades/simulates
away like a cloud dispersing. Turbulence is
used in the fluid volume to push it around. The falloff grid cuts
out an "R" shape no matter where the density moves.
To
display a falloff for Fluid Effects
- To
turn on the falloff display, select the fluid container and in the
fluidShape Attribute Editor do the following:
- In
the Contents Method section, select Static
Grid from the Falloff Method drop-down
list.
- In
the Shading section, select Use
Falloff Grid from the Dropoff Shape drop-down
list.
- In
the Display section, select Falloff from
the Shaded Display drop-down list.
- Create
the falloff style either using a curve within a container or using
the Paint Fluids Tool.
See
To paint falloff for Fluid Effects or
To use a curve within a container to create falloff for Fluid Effects.
- Optionally,
in the Shading section of the fluidShape Attribute
Editor, adjust the Edge Dropoff value.
A value of 0.5 is recommended for the Edge Dropoff when
working with Use Grid.
To
paint falloff for Fluid Effects
- Select
the Fluid Effects grid.
- Select
Fluid Effects > Add/Edit Contents > Paint Fluids Tool > .
The Paint Fluids Tool settings
window appears.
- Select Falloff from
the Paintable Attributes drop-down
list.
Before painting, be sure to set the falloff
display settings as in
To display a falloff for Fluid Effects.
- Paint
the fluids grid to create the falloff shape.
To
use a curve within a container to create falloff for Fluid
Effects
- Select
the Fluid Effects grid and Shift-select
the desired curve.
- Select
Fluid Effects > Add/Edit Contents > With Curve > .
The Set Fluids Contents
With Curve Options window appears.
- Do
the following:
- Turn
on the Density checkbox.
- Turn
on the Falloff checkbox.
- Adjust
the Falloff and Radius values.
- Click Apply
and Close.
The curve now represents the falloff shape.
To
cache the falloff data
- In
the fluidShape Attribute Editor (Contents
Details section > Grids Cache subsection),
check the Read Falloff checkbox.