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This setup requires Phoenix 5.20.00, V-Ray 6 for 3ds Max 2019 and Chaos Scatter 2.5 or newer. You can download official Phoenix and V-Ray builds from https://download.chaos.com. If you notice a major difference between the results shown here and the behavior of your setup, please reach us using the Support Form.

This tutorial shows how to create a cloudscape that changes from a sunny day to a stormy night. We'll start by creating various cloud types, such as cumulus, anvil, and stratus. Then we will load them into multiple VRayVolumeGrids, integrated into a single scene. We will manually place a few hero clouds in the shot and then use Chaos Scatter to scatter some generic cloud assets over the region. Once we finish the cloudscape for the daytime scene, we will utilize PFlow to strike lightning from the clouds, for the stormy night scene.

For realistic cloud shading, we will tweak the value of the Phase Function of the simulators.

At the end of the tutorial, we will color-correct the image with the V-Ray Frame Buffer, and we will make the shots more cinematic by using V-Ray Light Mix. This allows us to adjust the key-to-fill light ratio without rendering the image again.

The final video is a mix of the daytime and night-time shots with a transition composite.

The Download button provides an archive of the scene files.

This is an extensive tutorial, which might be overwhelming at first glance. To make it easier to follow, we have created a workflow diagram that illustrates how the article is structured. The tutorial is divided into three major stages:

1. Asset creation: In this phase, we generate various cloud assets using Phoenix Fire/Smoke Simulators. This includes hero clouds such as Cumulus_A, Cumulus_B, and Anvil_Cloud. We also generate some generic clouds that will be scattered in the scene using Chaos Scatter in the next stage. These cloud assets are saved as *.aur cache files.

2. Scene assembly: Once clouds of all types are ready, we load the *.aur files into one scene (cloudscape_daytime_start.max) using VrayVolumeGrid. First, we position our hero clouds and then fill the background and foreground with the generic clouds using Chaos Scatter. Finally, we create a VrayVolumeGrid for the environmental fog. We then render out the sequence for the daylight cloudscape.
3. Lighting and particle effects: Next, we add some lighting effects using PFlow. We adjust the lighting conditions by adding some Omni lights and tweaking the Light Mix. We then render out the sequence as a stormy night.

Scale is crucial for the behavior of any simulation. Large-scale simulations appear to move slower, while medium and small-scale simulations display lots of vigorous movement. When you create your Simulators, have a look at the Grid rollout where the real-world size of the Simulator is shown. If it cannot be changed, you can cheat the solver into working as if the scale is larger or smaller by changing the Scene Scale option in the Grid rollout.

The Phoenix solver is not affected by how you choose to view the Display Unit Scale - it is just a matter of convenience.

Since the height of a cumulus cloud is approximately 1000 meters, we have set the Scene Scale to Metric Meters.

The final scene contains a total of seven VrayVolumeGrids, each loaded with an *.aur file for a specific type of cloud: Cumulus_A, Cumulus_B, Anvil_cloud, Cloud_for_scatter_near, and Cloud_for_scatter_far. Each VrayVolumeGrid has a different smoke color for easy identification. We have also added an extra VrayVolumeGrid for the environmental fog.

The final assembly scene contains the following elements:

1. VRayCam for rendering. The camera is tilted and animated as if we are on an airplane that is flying up.
2. V-Ray Sun & Sky setup is used for the daytime scene lighting.
3. Omni_Cumulus_A, Omni_Cumulus_B, and Omni_Anvil are for the stormy night scene. All of these Omni lights are animated to mimic a lightning effect.
4. Two Chaos Scatter objects are used: one scatters the high-resolution Cloud_for_scatter_near in the foreground, and the other scatters the lower-resolution Cloud_for_scatter_far in the background.
5. Line_Areas_Near and Line_Distribute_Near splines are used to define the region that Chaos Scatter_Near uses to scatter clouds. Line_Distribute_Far splines are used to define the region that Chaos Scatter_Far uses to scatter clouds.
6. Two Particle Flows are used for the night-time lightning: PF Source 001 is positioned within Anvil_cloud, while PF Source 002 is placed inside Cumulus_A. Both emit particles using Lightning_branch as shape instances.
7. PCloud_Stars is used to create a background of stars.

Here are more details about the PFlow setup. As you can see, the particle system uses Group_Lightning as a Shape Instance. Both have VRayLightMtl applied, so their particles illuminate the scene.

Click on the Time Configuration icon ( ) and set the Animation Length to 90, so that the Time Slider goes from 0 to 90.

Camera Settings

Lighting for daytime

Lighting for stormy night

In the daytime scene, the middle ground is populated with highly-detailed cumulus and anvil clouds. Additionally, there are foggy clouds scattered in the distance, and some generic clouds scattered in the foreground. The stratus clouds intersect with these various types of clouds. The cloud shading is noteworthy, with beautiful and realistic forward scattering in its volumetric shading.

In the stormy night scene, the environment is foggier than during the daytime. Lights illuminate the large cumulus and anvil clouds. Lightning can be observed discharging from the clouds and flashing across the cloudscape.

Instead of scattering the same type of clouds throughout the sky, we are going to create three different types of clouds. This will enhance the realism of the cloudscape. We will create each of these assets in separate 3ds Max scenes and then assemble them in another dedicated scene.

The types of clouds we are going to create are cumulus, cumulonimbus (also known as anvil clouds), and stratus. Each of them looks different and is generated using a different method.

Let's start creating assets for the scene, beginning with the main cumulus cloud - the Cumulus_A.

Please open the provided Cumulus_A_start.max scene file. To save you some time, we have prepared three planes in the scene, each with the Shell, Edit Poly, and Noise modifiers applied, needed to break up the emitted smoke and make the clouds more diverse and asymmetric.

For example, we applied Shell, Edit Poly and Noise Modifiers to Plane002. While in Edit Poly mode, we select the top face of the geometry (marked in red), and set its face ID to 1. We set the face ID of the rest of the faces to 2.

This table shows the details of the three plane geometries with various modifier settings.

Let's create a simulator now. Go to Create Panel > Create > Geometry > PhoenixFD > FireSmokeSim. Rename the simulator to PhoenixFDFire_Cumulus_A.

The exact position of the Phoenix Simulator in the scene is XYZ: [0.0, 0.0, -40.0].

Open the Grid rollout and set the following values:

Select the Output rollout and enable the output of the Grid Smoke and Grid Velocity channels. We don't need the Temperature channel as we won't render fire.

Any channel used after the simulation is done, needs to be cached to disk. Such as:

Go to Create Panel > Create > Helpers > PhoenixFD > PHXSource. Rename it to PHXSource_Cumulus_A_001.

Press the Add button and select the Plane001 geometry from the viewport or from the Scene Explorer.

Set up the PHXSource_Cumulus_A_001's properties:

Changing the Noise parameters greatly influences the simulated cloud. It is recommended that you experiment with different settings once you've completed this tutorial. If you want to recreate the same result as shown here, follow the instructions exactly.

Keyframes for the FIre/Smoke Source's Outgoing Velocity

Repeat the same procedure for adding two more Phoenix Sources in the scene. Rename them to PHXSource_Cumulus_A_002 and PHXSource_Cumulus_A_003, respectively. Add Plane002 to the emitter nodes in PHXSource_Cumulus_A_002 and add Plane003 to PHXSource_Cumulus_A_003's emitter nodes.

Use the table to adjust the Outgoing Velocity of the Phoenix Sources.

Select the Simulation rollout of the PhoenixFDFire_Cumulus_A Simulator. We only need to simulate 10 frames, so set the Stop Frame to 10. Press the Start button to simulate.

This is a voxel preview of the current animation. The cloud appears too short.

In the Dynamics rollout of the simulator, increase the Steps Per Frame to 10. Run the simulation again. The Source emits fluid with very high velocity, so more Steps Per Frame are needed to capture it better.

This is the voxel preview of the current animation. As you can see, the height of the cloud has increased significantly.

Select the PhoenixFDFire_Cumulus_A Simulator and in the Dynamics rollout change the Fluidity Method to PCG Symmetric, with a Quality of 100. Run the simulation again.

This voxel preview shows the current animation.

To define the shape of the cloud more, let's edit the model of Plane001. First, select Plane001 and go to the Modifier panel. Then, add an Edit Poly Modifier and navigate to the Selection rollout. Click on the Polygon button, and then use the Ribbon's By Random option to randomly delete 30% of the faces.

After deleting, assign a Polygon ID of 1 to the top faces, and set an ID of 2 for the rest of the faces. Finally, run the simulation again to see the updated cloud shape.

This voxel preview shows the current animation. Now we see a more defined shape of a cumulus cloud.

To create a more natural-looking cloud, we can add some noise to the simulation. To achieve this, let's increase the Noise value for the Outgoing Velocity to 3.0 for all three PHXSources in the scene.

Additionally, select PhoenixFDFire_Cumulus_A and navigate to the Dynamics rollout to increase the Randomize Amount to 0.2.

Run the simulation again.

This voxel preview shows the current animation. Now we have a more organic-looking cloud.

To bring more realism to the cloud, let's add some forces to the scene. Go to the Create panel > Helpers > PhoenixFD and click on PHXTurbulence. Create a Phoenix Turbulence in the scene.

Then we add a Phoenix Plain Force, a simple directional force in the scene. Go to Create panel > Helpers > PhoenixFD and add a Phoenix Plain Force in the scene.

Now we are ready for the final simulation. Let's increase the grid resolution of the simulator. Make the following changes:

With the new grid resolution and forces in the scene, click on Start to run the final simulation for Cumulus_A.

This voxel preview shows the final animation.

Run a test render of frame 10 with the default volumetric settings. This helps assess what changes are needed to improve the look of the simulation.

Select thePhoenixFDFire_Cumulus_A Simulator and go to its Volumetric Render Settings.

Increasing the value for Light Cache Speedup speeds up the render, but it also lowers the quality of the Volume Light Cache. If dark cubic grid artifacts start forming on the smoke, the parameter is set too high. For more information, visit the Volumetric Rendering In-Depth page.

In this case set the Volume Light Cache to disabled as it will produce cleaner render result.

Alternatively, you can load up a render preset from the Cloud_render_preset.tpr file, that is provided in the sample scene.

With the new volumetric settings , run a test render of frame 10. This is the asset for Cumulus_A.

There's already one cumulus cloud in the scene. Now we will create another variant for the same type. You can open the scene "Cumulus_B_final.max" and save time, as we have already prepared all the required elements and configured the settings there. It is essentially similar to Cumulus_A.

This table shows the details for all three plane geometries in the scene.

This table shows all the settings for the three PHXSouces in the scene.

Here are the settings for the simulator - PhoenixFDFire_Cumulus_B:

The exact position of the Phoenix Simulator in the scene is XYZ: [308.0, -116.5 -40.0].

Open the Grid rollout and set the following values:

The simulator is loaded along with the Cloud_render_preset.tpr, so the volumetric settings are all set for the final render.

Select the Simulation rollout of the PhoenixFDFire_Cumulus_B Simulator. We only need to simulate 7 frames, so set the Stop Frame to 7. Press the Start button to simulate.

Run a test render of frame 7. This is our asset for the Cumulus_B cloud.

Open the scene "Cloud_for_scatter_far_final.max", where we have already prepared all the necessary elements and configured the settings for you. The setup is essentially the same as the previous two. However, the main difference is that since it is far from the camera, this cloud has a low-resolution grid to optimize performance.

This table shows the details for all three plane geometries in the Cloud_for_scatter_far scene.

This table shows all the settings for the three PHXSouces in the scene.

Here are the settings for the PhoenixFDFire_Scatter_far Simulator:

The exact position of the Phoenix Simulator in the scene is XYZ: [95.0, -327.0 -40.0]

Open the Grid rollout and set the following values:

The simulator is loaded along with the Cloud_render_preset.tpr, so the volumetric is all set for the final render.

Select the Simulation rollout of the PhoenixFDFire_Scatter_far Simulator. We only need to simulate 4 frames, so set the Stop Frame to 4. Press the Start button to simulate.

Run a test render of frame 4. This is our asset for the Cloud_for_scatter_far cloud.

Open the scene "Cloud_for_scatter_near_final.max", where we have already prepared all the necessary elements and configured the settings for you.

This table shows the details for all three plane geometries in the Cloud_for_scatter_near scene.

This table shows all the settings for three PHXSouces in the scene.

Here are the settings for the PhoenixFDFire_Scatter_near Simulator:

The exact position of the Phoenix Simulator in the scene is XYZ: [183.0, -63.0 -42.0].

Open the Grid rollout and set the following values:

The simulator has the Cloud_render_preset.tpr loaded, so the volumetric is all set for the final render.

Select the Simulation rollout of the PhoenixFDFire_Scatter_near Simulator. We only need to simulate 7 frames, so set the Stop Frame to 7. Press the Start button to simulate.

Run a test render of frame 7. This is our asset for the Cloud_for_scatter_near cloud.

We created assets for all the cumulus clouds and can move on to creating another type of cloud.

To get started, open the Anvil_cloud_start.max scene. We have prepared a geometry, a camera, and a VraySun for you to use. An anvil cloud is essentially a cumulus cloud before it reaches the ceiling of the stratosphere, so we can apply the experience we gained from making the cumulus clouds to the anvil cloud. Therefore, we will skip some of the steps and focus more on the formation of the distinctive "anvil" shape of this cloud type.

Rename the box to Box_Voxel_Tuner.

Set its Length, Width and Height to 8160.0m, 900.0m and 940.0m, respectively. Set the Segs for all axes to 1.

The exact position of the Box_Voxel_Tuner is XYZ: [125.0, -223.0, 808.0].

Since the Box_Voxel_Tuner is only used for the Voxel Tuner in a later step, we don't have to render the geometry. In its Object Properties, disable the Renderable checkbox and enable See-Through.

Several modifiers have been applied to the plane geometry, which uses the same settings as the planes for the Cumulus Cloud. To create the desired effect, the Phase of the Noise modifier is animated from a value of 1, at frame 0, up to a value of 4, at frame 15.

In the sample scene, we have set up a simulator for you. The simulator is named PhoenixFDFire_Anvil.

The exact position of the Phoenix Simulator in the scene is XYZ: [0.0, 0.0, -40.0].

Open the Grid rollout and set the following values:

The simulator is loaded along with the Cloud_render_preset.tpr, so the volumetric is all set for the final render.

In the Dynamics rollout of the PhoenixFDFire_Anvil, we have set the Fluidity Method to PCG Symmetric and the Quality to 100. However, we have decided to lower the Steps Per Frame to 5 instead of 10.

Set up the PHXSource_Anvil_Cloud's properties:

Changes to the Noise parameters greatly influence the simulated cloud. It is recommended that you experiment with different settings once you've completed this tutorial. If you want to recreate the same result as shown here, follow the instructions exactly.

Keyframes for the FIre/Smoke Source's Outgoing Velocity

Screenshot of the Outgoing Velocity keyframes

Apply the same PHXTurbulence settings as the ones in the Cumulus_A scene. Here are the details:

Select the Simulation rollout of the PhoenixFDFire_Anvil Simulator. We only need to simulate 11 frames, so set the Stop Frame to 11. Press the Start button to simulate.

This voxel preview shows the current animation. You can see a mushroom-like shape. Additional procedures are needed to achieve the distinctive "anvil" shape of this cloud type.

To replicate the atmospheric conditions of the Stratosphere, we can introduce a Phoenix Plain Force into the scene. To do this, go to Create Panel > Helpers > Phoenix and add a Phoenix Plain Force.

To make the visual effect more interesting, animate the Plain Force. Refer to the screenshot for the appropriate frame numbers and values. Set all tangents to Linear.

Go to Create Panel → Helpers → PhoenixFD → VoxelTuner. Create a Voxel Tuner anywhere in the scene.