Select Fluids > Add/Edit Contents > Paint Fluids Tool > 
to specify tool settings. Attributes unique to the Paint Fluids Tool in the Paint Attributes, Stroke, and Display sections are described below. For descriptions of other standard attributes in all other sections, see Artisan Tool Settings.
Paint Attributes
- Auto Set Initial State
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When this option is on (the default), the current state of the fluid (any Density, Velocity, Temperature, Fuel, Color, or Texture Coordinate values in dynamic grids) is saved automatically when you quit the Paint Fluids Tool, change the current time, or change your selection. If this option is off and you do not set the initial state of the fluid before playing or stepping through a simulation, the original painted values are lost.
You can manually set the initial state at any time by selecting , and you can clear it by selecting . For more information, see Fluids initial state.
- Paintable Attributes
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Select which property you want to paint.
Because Density is required to for Fuel to have an effect, you can simultaneously paint Density and Fuel values.
Similarly, because Color only displays in a grid where there is Density, you can simultaneously paint Density and Color values.
If you select Color, or Density and Color, be aware that the default grid color is green/brown (close to RGB 0.4 0.4 0.3). If this is not an acceptable grid color, flood the color grid with the color you want and set it as your initial state, see Flood a container with values and Fluids initial state.
By default, when you paint a property value, only that value displays. You can view all values in the container as they will render by changing Shaded Display in the Display section to As Render.
Select Falloff to paint falloff edges for the display of fluids, so that you can prevent the fluid from appearing in part of the volume. See Define an arbitrary falloff region for fluid containers.
- Color Value
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This setting is available only when Color, or Density and Color are selected as the Paintable Attribute. Click the Color Value box to open the Color Chooser and select the color you want to paint.
Velocity Direction
Velocity has both magnitude and direction. The Value setting defines the magnitude of the velocity you paint. Select how to define the direction of painted velocity strokes using the Velocity Direction setting. Velocity vectors display as you paint Velocity (Draw Velocity is turned on in the Display section of the Tool Settings window).
- From Stroke
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The direction of the velocity vector value comes from the direction of the brush along the current paint slice.
- As Specified
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The direction of the velocity vector value comes from the Specified X, Y, and Z boxes that become available when you select this option.
Paint Operation
Select an operation to define how you want painted values to be affected.
- Replace
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Replaces the values you paint over with the specified Value and Opacity.
- Add
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Adds the specified Value and Opacity to the current voxel values you paint over.
- Scale
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Scales the values you paint over by the Value and Opacity factors.
- Smooth
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Changes the values to be the average of the surrounding values.
- Value
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Set the value to apply when you perform any of the painting operations.
- Min/Max Value
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Set the minimum and maximum possible paint values. By default, you can paint values between 0 and 1. Setting the Min/Max Values you can extend or narrow the range of values. Negative values are useful for subtracting values. For example, if you set Min Value to -1, Value to -0.5, and select Add for the operation, you would subtract 0.5 from the values you paint. Positive values are used as multipliers.
Clamp
Select whether you want to clamp the values within a specified range, regardless of the Value set when you paint.
- Lower
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Turn this on to clamp the lower value to the specified Clamp Value. For example, if you clamp Lower and set the lower Clamp Value to 0.5, the values you paint will never be less than 0.5, even if you set the Value to 0.25.
- Upper
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Turn this on to clamp the upper value to the specified Clamp Value. For example, if you clamp Upper, set the upper Clamp Value to 0.75, and set Value to 1, the values you paint will never be greater than 0.75.
- Clamp Values
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Set the Lower and Upper values for clamping.
- Flood
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Click Flood to apply the brush settings to all the attribute values on the selected node. The result depends on the brush, value, paint operation, and other brush settings defined when you perform the flood.
Display
Use the settings in this section to define how the brush and property values display. In addition to many of the standard Artisan stroke settings, the Paint Fluids Tool has the following options.
Shaded Display
Select how you want the property values to display when in shaded display mode.
- Current Attribute
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Displays only the values for the property selected in Paintable Attributes.
If you paint Density and Fuel at the same time, Density values are represented by the opacity of the shaded values, while Fuel values are represented by a ramp of colors from blue (values of 0) to yellow (values of 1).
If you paint Density and Color at the same time, Density values are represented by the opacity of the shaded values, while Color is represented by the Color Value.
- As Render
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Displays the fluid as it will render. This is the same as setting the Shaded Display attribute in the Attribute Editor to As Render. See Shaded Display.
- Draw Velocity
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Turn this option on to display velocity vectors. This is the same as turning on Draw Velocity in the Attribute Editor. See Velocity Draw. Draw Velocity is turned on by default when you paint velocity.