Creating Non-dynamic Cloud Using Fluid Effects In Maya

Posted by Suraj Kayastha in Articles, Graphics, Maya Tutorials

In this tutorial, I am going to teach you how to create a static/non-dynamic cloud using Fluid effects in Autodesk Maya.

First we need to create a container. To create a 3D fluid container,
Select fluid effects > create 3D container

Set the container options as follows, and then click Apply and Close:

X Resolution: 50

Y Resolution: 5

Z Resolution: 60

X Size: 50.0

Y Size: 5.0

Z Size: 60.0

Now since the container is ready, we need to add fluid to the container.

For a cloud bank, Density is the only property you need to define—the other properties are typically used in dynamic solving.

  1. Dolly and tumble the scene view to see the entire container.
  2. With the fluid container selected, show the Attribute Editor(CTRL+A), and click on the fluidShape1 tab.
  3. In the Contents Method section of the Attribute Editor, set:
    1. Density: Gradient
    2. Density Gradient: Constant

Set Velocity, Temperature, and Fuel properties to Off. (They’re not used in this effect.)

The fluid is ready, now we need to apply proper shader to the fluid to give it the actual looks of a cloud.

  1. Open the Shading section in the Attribute Editor.
  2. In the Color subsection, change Color Input to Density.

The Density values in the container will now take on the colors defined on the color bar. Leave the color white to make the clouds appear white.

  1. In the Opacity subsection, check that the Opacity Input is set to Density.

The opacity represents how much the Density will block light.
Texturing the density of cloud makes the fluid cloud more realistic.
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.

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.

Open the Textures section in the Attribute Editor.

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.

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.

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.

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

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

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.

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).

-Click the first dot on the Opacity graph to select the position marker. Position markers mark the location on the graph from left to right (the Opacity Input value). The outline of the dot is white when a position is selected.

-Change Selected Position to 0.10 to change the position of the marker.

The position marker moves to the right. Now, for Density values between 0 and 0.10, the Opacity values will be 0. This means that Density that was previously partially transparent will be completely transparent.

The more transparent areas of cloud disappeared, but now the solid areas of cloud are less opaque.

-Click on the graph to create a new position marker.

-Change the marker position and value as follows:

Selected Position: 0.15

Selected Value: 0.30

Density values that are greater than 0.15 are now more opaque, and the transition between areas of total transparency (Opacity 0), and areas where the Density becomes more visible (Density 0.15) is less gradual.
Adding self shadow to the cloud.

Give the clouds some depth by adding self shadowing. Self shadowing causes the fluid to cast shadows on itself using a single internal directional light at -1, -1, -1.

  1. In the Attribute Editor, under the fluidShape1 tab, open the Lighting section.
  2. Turn on Self Shadow.

The clouds now have some darker areas on them, giving them some depth.

  1. In the Display section, change Boundary Draw to None to hide the container. This gives you a better idea of how the fluid will look before you render it.


Hope this tutorial helped you a bit to create a concept in static clouds using Fluid effects in Autodesk Maya.