Set fluid attribute ramps

Some fluid attributes have ramps that let you remap the raw fluid properties into the values used when rendering. The following fluid attributes are set using ramps:

• Environment
• Color
• Incandescence
• Opacity
• Wave Height on the Ocean Shader/Texture node

To set an attribute ramp

1. In the scene view, select the fluid object for which you want to set an attribute ramp.
2. In the Attribute Editor, select the fluidShape tab.
3. In the Attribute Editor, locate the attribute ramp you want set, and then create the ramp by setting values for Selected Position and Selected Value.

   For example, to define the colors on the fluid Color ramp, you can add position markers to the ramp, and then change the color at the markers by doing the following:

   • To select a position on the ramp, click the dot indicating the marker.

     The selected marker has a white outline around the dot. You can click the color swatch and assign a color to the marker.

   • To add a marker, click the ramp.
   • To move a marker, drag the marker dot left or right, or select the marker and type the destination position in the Selected Position box.
   • To delete a marker, click the square x at the marker position.
   
4. Set an Interpolation method to specify how values blend between each Selected Position (point) on ramp. You can select from the following options:
   • None does not interpolate the values, meaning that the curve is flat between points.
   • Linear interpolates values using a linear curve.
   • Smooth interpolates values using a curve, so that each value on the ramp dominates the region around it, then blends quickly to the next value.
   • Spline interpolates values using a spline curve, taking neighboring indices into account for greater smoothness.

   See Interpolation.

5. Set the ramp’s Input to specify which fluid property is used to map the input attribute value.

   For example, a color ramp with a black, orange, and yellow mapped to Density appears similar to the following:

   
6. Set the ramp’s Input Bias. See Input Bias.
   

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