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The final shot we aim at involves not just water, but also Fire and Smoke. A particle flow (PFlow) system is used as a source for the missile smoke trail. The smoke is simulated using Phoenix Fire/Smoke simulator.

For the liquid, we add three Liquid sources to achieve the final effect. One is linked to the missile, one to a Geosphere, and the third one to a Cone geometry that emits splash particles. The liquid and the particles are simulated with a Phoenix Liquid Simulator. Together all these compose a convincing submarine-launched ballistic missile effect.

This simulation requires Phoenix 4.41 Nightly Build from 08 July 2021 and V-Ray 5 Official Release for 3ds Max 2018 at least. You can download nightlies from https://nightlies.chaos.com or get the latest official Phoenix and V-Ray 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.

The Download button below provides you with an archive containing the scene files.

Scale is crucial for the behavior of any simulation. The real-world size of the Simulator in units is important for the simulation dynamics.

Large scale simulations appear to move slower, while mid-to-small scale simulations have lots of vigorous movements.

When you create your Simulator, check the Grid rollout where the real-world sizes of the Simulator are shown. If the size of the Simulator in the scene cannot be changed, you can trick 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. Setting the units to Meters is a reasonable choice.

Go to Customize → Units Setup and set Display Unit Scale to Metric Meters. Also, set the System Units so that 1 Unit equals 1 Meter.

The final scene contains the following elements:

1. Ship object for creating a sense of scale in the scene;
2. Missile geometry;
3. Three Liquid sources, each using the Missile, GeoSphere and Cone as emitters, respectively;
4. Phoenix Fire / Smoke source for smoke trail;
5. Phoenix Plain Force as a wind force in the scene;
6. Phoenix Fire/Smoke Simulator;
7. Phoenix Liquid Simulator;
8. V-Ray Physical Camera (VRayCam) for rendering;
9. V-Ray Sun & Sky setup for lighting.

A close-up for the final scene contains the following elements:

1. Cone geometry as a liquid source;
2. GeoSphere geometry as another liquid source;
3. Missile object;
4. Particle Flow node: PF Source that is linked to the moving missile object.

Set the Time Configuration → Animation Length to 120 so that the Time Slider goes from 0 to 120.

Camera Settings

Lighting

The missile shot has few key features:

• The first one is, when the rocket launches from underwater, the smoke trail drifts from left to right because of the wind. The direction of the ocean wave matches the Plain Force orientation in the scene.
• Secondly, once the missile launches, a large number of splashes comes out of the sea. The smoke trail is bright white with a bluish tint. We can see a reflection of the hot smoke on the ocean surface, even though the rocket is flying out of the camera. This means that the Fire/Smoke simulator must be tall enough for an out of camera frustum.

Though the smoke and liquid are simulated independently, parts of the splash/mist /foam overlap with the smoke, making the shot visually more convincing.

Here are the general stages of the SLBM shot:

1. The missile launches at frame 5 and it gradually loses speed because of gravity.
2. At frame 50, the missile starts to ignite. You can see hot white smoke coming out of the missile nozzle while it is changing its trajectory.
3. At frame 59, the missile ignition fire reaches the ocean surface, creating lots of water splashes.
4. At frame 65, the missile enters the acceleration stage, rushing to the sky at full speed.

The Particle Flow settings here are provided only as a starting point for the Phoenix Simulation. Feel free to tweak and adjust them according to your scene.

Here is a preview animation of the particle simulation. This particle system is pretty straightforward - there is only one event in the system. It is linked to the keyframed missile object.

Particles are shown in dark yellow color.

Here you can see the Particle View of the particle systems. For the Birth operator, the Emit Start is set to 50 as the missile is ignited at frame 50.

The Speed for the particles is set to 125.0 m with variation set to 20.0 m.

The particle age is controlled by the Delete operator, with a Life span set to 1, so the particles don't last long.

Let's create a simulator now. Go to Create Panel → Create → Geometry → PhoenixFD → FireSmokeSim.

The exact position of the Phoenix Simulator in the scene is XYZ: [0.0, 0.0, 3.25].

Open the Grid rollout and set the following values:

Select the Simulator → Output rollout and enable the output of Temperature, Smoke, and Velocity Grid Channel. 

Now, let's create a Phoenix Fire/Smoke Source in the scene. Go to Create Panel → Create → Helpers → PhoenixFD → PHXSource. Rename it to PHXSource-Missile-Smoke.

Press the Add button to choose which geometry to emit and select the PF Source entry in the Scene Explorer.

When you pick the PF Source node, the Available Events dialog pops out. Choose both the "PF Source 001→PF Source 001" and "PF Source 001→Event 001".

For the PHXSource-Missile-Smoke:

Now, let's go to Graph Editors/Track View → Curve Editor and set keys to the curve of PHXSource-Missile-Smoke's Outgoing Velocity. Set keyframes to Outgoing Velocity, so it can change over time.

Each frame and value are shown in the screenshots.

Here is a table with keyframes for the PHXSource-Missile-Smoke's Outgoing Velocity. 

Here is a table with keyframes for the PHXSource-Missile-Smoke's Temperature you can use. 

Select the Simulation rollout of the Phoenix Fire/Smoke Simulator. Since the smoke animation starts at frame 50, set the Start Frame to 49. You don't have to simulate the full length of the animation. Only a sample is enough, so set Stop Frame to 90.

Press the Start button to simulate.

Here is a preview of the simulation up to this step.

To improve the fluid simulation, we switch the conservation method to PCG Symmetric in the next step.

Select the Phoenix Fire/Smoke Simulator and change the Conservation Method to PCG Symmetric, with a Quality of 80.

The PCG Symmetric option is the best method to use for smoke or explosions in general, preserving both detail and symmetry. The high Conservation Quality allows the smoke to swirl better. For more in-depth information, check the Conservation documentation.

Here is a preview animation of the simulation with the PCG Symmetric option switched on.

Now the smoke swirls better, but it stays hot for too long. To tackle that, select the Phoenix Fire/Smoke Simulator and go to the Dynamics rollout. Increase the Cooling to 3.

With the new dynamics settings, run the simulation again.

Now the hot smoke cools faster. The short tail of the hot smoke combined with the long streak of the cool smoke makes it look more convincing.

To make the smoke float up faster, select the Fire/Smoke Simulator, go to the Dynamics rollout and set the Smoke Buoyancy to 20.0. With the new Dynamics settings, run the simulation again.

This example shows the scene after adjusting Buoyancy.

For additional realism of the simulation, we use a Phoenix Plain Force to simulate the effect of wind.

Go to Create Panel → the Helpers tab → Phoenix and add a Phoenix Plain Force. This is a simple directional force.

The exact Position of the Plain Force in the scene is XYZ: [23.0, -69.0, 19.0].

Rotate it so that it points to the minus X direction and set the Strength to 5.0 m. Set the Drag to 0.1. Enable the Apply Force Behind Icon option.

The exact Rotation of the Plain Force in the scene is XYZ: [-90.0, 0.0, 0.0].

Remove Liquid from the Affect list, because later that causes it to blow on the ocean surface. The ocean liquid is controlled purely by displacement.

In order to get a more detailed result we also increase the Grid Resolution by lowering the Cell Size for the final simulation.

Open the Grid rollout and set the following values:

As seen in the example, the smoke is slowly drifting to the right.

Let's give the PHXSource_Missile_Smoke some randomness. Set its Noise to 0.05.

Run the simulation again.

Here's how it looks like.

The Randomize options add random fluctuations in the fluid's velocity for each grid voxel. It reduces the smoke's trail volume, producing interesting effects.

With the Fire/Smoke Simulator selected, go to the Dynamics rollout. Set the Randomize Amount to 0.15.

To simulate the full length of the animation, go to the Simulation rollout and enable the Timeline option for the Stop Frame. Press the Start button to simulate.

Here is a preview of the sim animation so far.

The smoke looks thin and dark.

Go to the Fire/Smoke Simulator → Rendering rollout and click on the Volumetric Options. Adjust the color gradient and the curve as shown in the image.

In the Smoke Color rollout, set the Constant Color to pure white (RGB: 255, 255, 255). Then, increase the Master Multiplier to 2.0. Set the Simple Smoke Opacity to 0.99.

Alternatively, you can load up a Rendering Preset from the SLBM_rendering_preset.tpr file that is provided in the sample scene.

Here's a render of the current step of this scene.

To further enhance the realism of the smoke trail, select the Phoenix Fire/Smoke Simulator, go to Rendering rollout → Volumetric Options. In the Smoke Opacity rollout, set the Absorption Constant Color to RGB (96, 96, 117).

Now we have a white smoke trail with a subtle bluish tint. The ratio of the hot afterburn to the cold smoke trail looks convincing.

The Fire/Smoke Simulation is completed. Now let's move on to the liquid part of this tutorial. In the Scene Explorer, click on the Eye Icon on the left of PhoenixFDFire node entry to hide the Phoenix FD Fire/Smoke Simulator.

Let's now take care of the liquid simulation. Go to Create Panel → Create → Geometry → PhoenixFD → PhoenixFDLiquid.

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

Open the Grid rollout and set the following values:

Select the Output rollout of the PhoenixFDLiquid. Leave everything at their default values.

Select the PhoenixFDLiquid → Scene Interaction rollout. Press Add and choose PF Source in the Scene Explorer.

Let's prompt the Available Events window. Choose both the "PF Source 001→PF Source 001" and "PF Source 001→Event 001" options and press OK. Now all PFlow particles are excluded from the liquid simulation.

Create a Phoenix Liquid Source in the scene by going to Create Panel → Create → Helpers → PhoenixFD → PHXSource. Rename it to LiquidSrc-Missile.

Press the Add button to choose which geometry to emit and add Missile entry to the Scene Explorer.

For the LiquidSrc-Missile:

Go to Graph Editors/Track View → Curve Editor and set keys to the curve of the Liquid-Missile's Outgoing Velocity. We set keyframes for the Outgoing Velocity, so it can change over time. The frames and values are shown in the screenshots.

Here is a table with keyframes of the Liquid-Missile's Outgoing Velocity. 

Enable the Foam option. When asked if you'd like a Phoenix Particle Shader generated for the Foam particles, select Yes. This automatically sets up the link between the Foam particles group, the Shader, and the Liquid Simulator. Same goes when you enable the Splash/Mist option for the Splash.

Now there are two Particle Shaders in the scene. Rename them to ParticleShader-Foam and ParticleShader-Splash respectively.

Set the Mode of the ParticleShader-Foam to Points. Leave the other settings at their defaults for now.

As for the Mist particle, you have to create a new Particle Shader for it manually.

Go to Create Panel → PhoenixFD and press the PHXFoam button to create a new Particle Shader in the scene. Rename it to ParticleShader-Mist.

With the PhoenixFDLiquid Simulator selected, simulate one frame. This step allows Phoenix to generate a Foam/Splash/Mist particles list in the scene.

With the ParticleShader-Mist selected, go to the Modifier Panel. Press the Add button to choose the PhoenixFDLiquid entry in the Scene Explorer, then press OK.

Prompt the Available Events window and choose the Particle[Mist]of[PhoenixFDLiquid001]. Press OK.

Set the ParticleShader-Mist's mode to Fog. Disable the Volume Light Cache option.

Now all three Particle Shaders for the Foam/Splash/Mist particles are set.

You can see splashes coming out of the water when the missile is launched. But there are not enough splashes and the distribution of the particle formation is not optimal.

To see which particles are which more clearly, let's change the color swatches for the different particle types. Select the PhoenixFDLiquid in the scene and go to its Preview rollout. Set the Splash, Mist, and Foam to Blue (RGB: 0, 0, 255), Red (RGB: 255, 0, 0), and Green (RGB: 0, 255, 0) color respectively.

Disable the Liquid Preview by unchecking its Show option, so we can track the distribution of the Splash/Mist/Foam particles by their color.

Set Scale Color By to No Scaling for all particle types.

Here is a preview of the simulation.

In the Foam rollout, increase the Foam Amount to 10.0. Lower the Birth Threshold to 1.0m.

Run the simulation with the new settings.

More Foam particles are generated after the Missile launch. However, the Foam rises too fast and is cropped by the Simulator.

Select the Foam rollout. Set the Max Outsize Age to 4.0 and B2B Interaction to 0. Decrease the Rising Speed to 3.0m. and the Falling Speed to 30.0m.

Run the simulation with the new dynamics settings.

Now we have Foam particles shooting up and they continue flying even outside of the Liquid Simulator's boundaries.

Select the Splash/Mist rollout. Reduce the Splash to Mist to 0.05 and increase the Mist Amount to 300.0. Set the Max Outsize Age to 4.0.

Run the simulation again with the adjusted settings.

Let's check the simulation.

The shape of the Splash from the Missile is currently not what we are after. Also, the amount of Splashis not enough.

Let's create another Liquid Source in the scene by going to Create Panel → Create → Helpers → PhoenixFD → PHXSource. Rename it toLiquidSrc-Geosphere.

Press Add to choose which geometry to emit. Click on the GeoSphere entry in the Scene Explorer.

For the LiquidSrc-Geosphere:

Go to Graph Editors/Track View → Curve Editor and set keys to the curve of LiquidSrc-Geosphere's Outgoing Velocity.

Set keyframes for the Outgoing Velocity, so it can change gradually. The frames and values are shown in the screenshots.

Set keyframes for Tangents to Stepped, too.

Run the simulation again.

Now the splashes coming out of the sea are stronger.

Now let's create a Phoenix Liquid Source in the scene (Create Panel → Create → Helpers → PhoenixFD → PHXSource). Rename it to LiquidSrc-Cone.

Press the Add button to choose which geometry to emit. Click on the Cone entry in the Scene Explorer.

For the LiquidSrc-Cone: