Ok, by the end of this tutorial you should have a basic understanding of maya fluids and clouds you can use in any scene for future projects. Before i get into the nitty gritty of it all i'll explain the basic setup. It includes two maya fluids cube and a spotlight. One cube being the clouds and the other creating the blue haze/falloff effect of the sky.
This first part of the tutorial will show how to quickly create clouds with maya fluids.
First we need to create a 3D container from the Fluid Effects menu
When we open the first fluid rename it to clouds we intend on using this as our cloud layer. Firstly we want to change the properties of the cube. Change the size of the cube to 20,2,20 respectively. This increases the size of the cube. Now alter the resolution to 80,8,80. Increasing this will make the fluids more detailed when rendered.
You will notice several main attributes under the Contents Method tab. These are Density, Velocity, Temperature, Fuel and Colour Method. Make sure all of these are set to Off(zero) except for Colour Method which we want set to Use Shading Colour. The reason for this is because we don't want our clouds to move, we want them to just sit there....however you can play with settings to achieve a timelaps effect.
Ok now before we do anything else we want to go down to the Texture tab and turn tick Texture Colour and Texture Opacity. We do this now so we can see the changes we are about to make in the viewport. While we here change the Texture Type to Perlin Noise. Also at this point we want to turn on texturing in our viewport. To do this click on shading in the viewport you wish to view the clouds through. Change it from wireframe to smooth shade all.
Next we want to open the Shading tab. Change the transparency RGB values all to 0.091. This will change the over all opacity of the clouds. Also change the Edge Dropoff to about 0.485 so the clouds fade off at the edge of the cube Now we move onto the Colour tab. Here we need to set up a gradual fade from white to black. For this we will need 3 points. The first point should already be set to white and should be set to a postion of 0.000. click anywhere on the gradient to create a 2nd point. The selected postion of the 2nd point should be around 0.743, it's selected colour should be 0.656 for all RGB values. Repeat this process for the 3rd point making the selected position a value of 1 and the RGB values all 1. Change the Colour Input to Y Gradient. This will help create the effect of light comming from above the clouds.
I won't go into too much detail here seeing you know all about selected positions/selected values etc. You need 5 points for the opacity. The following is a list of the points, their selected positions and their selected values.
selected position = 1.000, selected value =.940
selected position = 0.814, selected value =0.820
selected position = 0.593, selected value =.0.600
selected position = 0.479, selected value =0.360
selected position = 0.429, selected value =0.000
Make sure the Opacity Input is set to constant and that Input Bias is set to 0.030. Open the Shading Quality tab and change Quality to a value of 3.000, this essentially is the sampling rate for the fluids.
Finally we want to alter some of the texture settings for the Perlin Noise we set up in the beginning. Change the Amplitude to 0.976, Ratio to 0.408, the Frequency Ratio to 2.835 and the Frequency to 1.942. Also turn on Inflection
The end result should look something like this in the viewport.
And the render.
This scene needs alot more work i.e. Haze and lighting but this will hopefully give you guys a footing into maya fluids. Sorry for it seeming rushed, i'll update it in the near future to explain in more detail.
This last pic im just updating this tutorial with, it's an example of two results you can achieve with this technique.