Texturing the contents of a fluid container

So far the container is filled with solid white Density. To create the cloud effect, you texture the Density so that some areas are transparent and some areas are opaque.

To texture the density of a fluid

  1. Turn on hardware texturing display so you can see the effect of the textures on the fluid without rendering by selecting Shading > Hardware Texturing from the scene view menu.
  2. Open the Textures section in the Attribute Editor.
  3. Turn on Texture Opacity to apply the current texture to Opacity values. The current texture is Perlin Noise, defined by Texture Type.

    Notice that the Density now has a slightly blotchy look to it, with areas that are more opaque and areas that are more transparent. This texture provides the standard 3D noise used in the 3D Solid Fractal texture included with Maya.

  4. Change Texture Type to Billow for a fluffy, cloud-like effect.

    The Billow texture is computationally intensive and therefore slower than the other texture types.

  5. Change the look of the texture by setting the following texture attributes:
    • Amplitude: 0.5
    • Depth Max: 4

    Decreasing the Amplitude makes the areas with low Density more transparent and the areas with high Density more opaque.

    Increasing Depth Max adds detail. Increasing it will also increase render time.

  6. Stretch the texture in the X direction by changing the X, Y, and Z components of the Texture Scale to 2, 1, 1.

  7. Change the following Billow texture attributes to make the “billows” less dense, more spotty, and with randomly different sizes.
    • Billow Density: 0.6
    • Spottyness: 2.0
    • Size Rand: 0.40

  8. Modify the Opacity so that areas in the container that are very dense appear less opaque, areas that have very little Density become totally transparent, and the transition between areas that are totally transparent and areas that are more opaque is less gradual.

    In the Attribute Editor, go to the Shading section. Look at the Opacity graph in the Opacity subsection. This graph represents the relationship between Opacity values and Density values (the Opacity Input).

    Opacity values range from 0 on the bottom (totally transparent, no opacity) to 1 on the top (totally opaque).

    Density values range from 0 on the left side (no Density) to 1 on the right side (high Density).

    So for the linear graph shown above, where Density values are 0, Opacity values are 0, making the Density totally transparent, where Density values are 0.5, Opacity values are 0.5, making the Density partially opaque, and where Density values are 1, Opacity values are 1, making the Density totally opaque.