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In this tutorial we demonstrate how to work with thinkingParticles in tandem with Phoenix FD. We generate bombs using thinkingParticles. When missiles hit the ground, bounced debris are procedurally created.

thinkingParticles contain velocity information and Phoenix FD can use them as sources for fire/smoke in order to produce realistic artillery explosions.

Also, we take advantage of the Time Base - Particle Age, a powerful feature of Fire/Smoke source. It allows us to animate the emission of fluid based on the age of each individual particle.

This simulation requires thinkingParticles 6, Phoenix FD 4.00 Official Release and V-Ray Next Official Release for 3ds Max 2015 at least. If you notice a major difference between the results shown here and the behavior of your setup, please send an email to support@chaosgroup.com.

The Download button below provides you with an archive containing the start and end scenes.

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, you must check the Grid rollout where the real-world extents of the Simulator are shown. If the size of the Simulator in the scene 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 FD solver is not affected by how you choose to view the Display Unit Scale - it is just a matter of convenience.

As the focus of this tutorial is a large-scale simulation, setting the units to Meters seems like a reasonable choice.

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

The final scene consists of the following elements:

1. Plane-bomb-emitter is a plane where bombs are generated;
2. thinkingParticles node (Thinking001);
3. Phoenix FD Fire/Smoke Simulator;
4. There are total of7 Phoenix FD Fire/Smoke Sources, each representing different component of the explosion;
5. V-Ray Sun&Sky for lighting;
6. V-Ray Physical Camera for rendering;
7. Shelled Plane001-collision for ground plane;
8. Car and Posts geometry for additional detail, as well as for creating a better sense of scale in the scene;
9. PlainForce as a wind force in the scene;
10. A point helper for camera shake.

Underneath the ground plane, at the right corner, you can find geometries that produce the explosion procedurally.

1. Bomb-Geo as the bomb itself;
2. Rock 01 ~ 06 are six geometries for debris;
3. Pointy, Cone_smaller, Con_bigger, Cylinder and Sphere_core are the geometries generated when the bomb hits the ground. They provide the position of the particle emission, allowing us to generate the raised dust, debris or particles for the major explosion.

Notice that these helper geometries affect the bouncing angle of the particles. For example, for the Cone_bigger geometry, the slope is roughly 45 degrees. Therefore, when the dust particles rise, the slope gets to be 45 degrees.

You can customize your explosion by adjusting the helper geometry.

 Camera Setting

Lighting

To cache the thinkingParticles simulation to disk, select the thinkingParticles node (Thinking001) in the Scene Explorer and open the Properties window.

Select Master Dynamic → Artillery_Explosion.

Under the Playback Cache section, select the Output Path for the cache files and press Record.

That's all. Once the thinkingParticles simulation is cached, we can proceed with the Phoenix FD Simulation.

Here is displayed a preview animation of the simulation in its current state.

As you can see, bomb_geo is generated from Plane_bomb_emtter. Once the missiles hit Plane001_collision, five different helper geometry instances are placed at that spot: Pointy, Cone_smaller, Con_bigger, Cylinder and Sphere_core. Then,

1. Major_explo particles are generated from the surface of Pointy_geo;
2. Upward_dust particles are generated from the surface of Sphere_geo;
3. Falling_dust particles are generated from the surface of Cone_smaller_geo;
4. V_dust particles seed A and V_dust particles seed B are generated from the surface of Cone_bigger_geo;
5. V_dust_A particles are generated based on the surface position of V_dust particles seed A. Similarly, V_dust_B particles are generated based on the surface position of V_dust particles seed B;
6. shockwave short particles are generated from Cylinder_geo;
7. shockwave long particles are generated from Cylinder_geo;
8. Debris particles are generated from Cone_bigger_geo, and use 6 of the rock geometries as instances.

Here is a list of thinkingParticles. It summarizes all the different particles and their geometry instances. All are color-coded, so you can easily recognize them in the viewport.

Anatomy of the Artillery Explosion

Here we show the final result of the explosion, so you can have a better idea of how the different elements look like.

Go to Modify Panel → Create → Geometry → PhoenixFD → FireSmokeSim.

The exact position of the Phoenix FD Simulator in the scene is XYZ: [ -15, 0, 0 ].

Open the Grid rollout and set the following values:

Select the Phoenix FD Simulator → Output rollout and enable the output of Temperature, Smoke, RGB, Velocity and Fuel Grid Channels. 

List of Fire/Smoke Sources and their settings

Let's create the sources.

Create two Phoenix FD Fire/Smoke Sources in the scene: Modify Panel → Create → Helpers → PhoenixFD → PHXSource. Rename them to PHXSource_V_Dust_A and PHXSource_V_Dust_B respectively.

Pressthe Add button to choose which geometry to emit and select the thinkingParticles node (Thinking001) entry in the Scene Explorer.

A pop-up window appears listing all Particle Groups of the thinkingParticles simulation. Choosethe Particles [V_dust_A] group and press OK.

Repeat the process above for V_dust_B by adding the [V_dust_B] group in its Emitter Nodes.

1. For PHXSource_V_dust_A

Set the Emit Mode to Volume Inject and Smoke to 1.0. Enable the RGB option and set it to dark gray color (RGB: 64, 61, 59); Motion Vel. to 1.0; Prt Shape to Sphere, custom; Custom Prt Size to 0.15 m.

From frame 17 to 26, animate the value of Inject Power from 1.5 to 0.0.

2. For PHXSource_V_dust_B

We name this source V_dust because its shape looks like V as the dust rises.

Set the Emit Mode to Volume Inject and Smoke to 1.0. Enable the RGB option and set it to dark gray color (RGB: 36, 27, 23); Motion Vel. to 1.0; Prt Shape to Sphere, custom; Custom Prt Size to 0.15 m.

From frame 17 to 26, animate the value of Inject Power from 1.5 to 0.0.

Go to Graph Editors/Track View → Curve Editor andcheck the curve of PHXSource_V_dust_A's Inject Power.

Set the first key frame to Tangents to Slow and the second key frame to Tangents to Fast.

Same applies for PHXSource_V_dust_B.

Set the Phoenix FD Simulator → Simulation rollout → Start Frame to 16 so that it matches the start frame of the thinkingParticles simulation.

Here is a Preview Animation of the simulation up to this step.

Add a Phoenix FD Fire/Smoke Source: Modify Panel → Create → Helpers → PhoenixFD → PHXSource. Rename it to PHXSource-major_explo.

Press the Add button to choose which geometry to emit from and select the thinkingParticles node (Thinking001) entry in the Scene Explorer.

A pop-up window appears listing all Particle Groups of the thinkingParticles simulation. Choose the Particles [Major_Explo] group and press OK.

Set the Emit Mode to Volume Inject and Smoke to 1.0. Enable the Fuel option. Enable the RGB option and set it to dark gray color (RGB: 1, 1, 1); Motion Vel. to 1.0; Prt Shape to Sphere, custom; Custom Prt Size to 0.2 m.

From frame 17 to 20 animate the value of Inject Power from 2.0 to 0.0.

Also, animate the value of Temperature from 2500 to 300.

You can go to Graph Editors/Track View → Curve Editor and check the curve of PHXSource-major_explo's Inject Power and Temperature.

For the Inject Power, set the first key frame to Tangents to Fast and the second key frame to Tangents to Slow as shown. For the Temperature, set the first key frame to Tangents to Slow andthe second key frame to Tangents to Fast.

To allow Phoenix FD to burn the fuel from Major_Explo source, select the PhoenixFDFire Simulator and go to the Fuel rollout. Check the Enable Burning option and leave all settings at their defaults.

Here is a preview animation of the simulation after the last step. We now see the explosion and the burning fuel, but the smoke looks too thin.

Let's see how to enhance it.

The default setting of the Smoke color is Constant color. Let's tweak the Smoke Color to get more variation.

Select the Phoenix FD Simulator → Rendering rollout and press the Volumetric Options button.

In the Volumetric Render Settings window set the Smoke Color Based on RGB. Set the Smoke Opacity based on Smoke and then adjust the curve as in the screenshot.

Here's a preview of the simulation with the render settings changed.

As you can see now, we now have thicker smoke appearance. The color variation of the smoke looks more convincing. However, V_dust appears too uniform and the smoke rises too fast. Let's tackle that.

Let's give V_dust some randomness.
Set both the PHXSource_V_dust_A and PHXSource_V_dust_B's Noise to 0.5.

Select the PhoenixFDFire Simulator in the scene. Go to Dynamics rollout. Set the Smoke Buoyancy to -2.0.

Run the simulation again.

Let's see a preview animation. Notice that V_dust now looks more organic. And the smoke rises more gently, it even falls on the ground with time.

Add a Phoenix FD Fire/Smoke Source: Modify Panel → Create → Helpers → PhoenixFD → PHXSource. Rename it to PHXSource-upward_dust.

Pressthe Add button to choose which geometry to emit from and select the thinkingParticles node (Thinking001) entry in the Scene Explorer.

A pop-up window appears, listing all Particle Groups of the thinkingParticles simulation.

Choose the Particles [Upward_dust] group and press OK.

Set the Emit Mode to Volume Inject and Smoke to 1.0.

Enable the RGB option and set it to white color (RGB: 220, 215, 212); Motion Vel. to 1.0; Prt Shape to Sphere, custom. and Custom Prt Size to 0.04 m.

From frame 17 to 25 animate the value of Inject Power from 10.0 to 0.0.

You can go to Graph Editors/Track View → Curve Editor and check the curve of PHXSource-upward_dust's Inject Power.

For Inject Power, set the first key frame to Tangents to Slow and the second key frame to Tangents to Fast.

With the PHXSource-upward_dust in the scene, run the simulation again.

We start to see more details in the explosion.

Add a Phoenix FD Fire/Smoke Source: Modify Panel → Create → Helpers → PhoenixFD → PHXSource. Rename it to PHXSource-falling-dust.

Pressthe Add button to choose which geometry to emit from and select the thinkingParticles node entry in the Scene Explorer.

A pop-up window appears listing all Particle Groups of the thinkingParticles simulation.

Choose the Particles [falling_dust] group and press OK.

Set the Emite Mode to Volume Inject and Smoke to 1.0. Enable the RGB option and set it to brown color (RGB: 92, 70, 52); Motion Vel. to 1.0; Prt Shape to Sphere, custom.; Custom Prt Size to 0.06 m.

From frame 17 to 67, animate the value of Inject Power from 1.0 to 0.0.

You can go to Graph Editors/Track View → Curve Editor and check the curve of PHXSource-falling-dust's Inject Power.

For the Inject Power, set the first key frame to Tangents to Slow and the second key frame to Tangents to Slow.

With the Falling_dust Fire/Smoke in the scene simulate again. The smoke trails are visible in the explosion now.

Create two Phoenix FD Fire/Smoke Sources in the scene: Modify Panel → Create → Helpers → PhoenixFD → PHXSource. Rename them to PHXSource_shockwave_short and PHXSource_shockwave_long respectively.

Pressthe Add button to choose which geometry to emit from and select the thinkingParticles node (Thinking001) entry in the Scene Explorer.

A pop-up window appears listing all Particle Groups of the thinkingParticles simulation. Choose the Particles [Shockwave_short] group and press OK.

Repeat the process above for Shockwave_long particle group.

1. For PHXSource_shockwave_short: Set the Emit Mode to Volume Inject; Inject Power to 1.0; Smoke to 0.25. Enable the RGB option and set it to light brown color (RGB: 176, 152, 126); Motion Vel. to 1.0; Prt Shape to Sphere, custom.; Custom Prt Size to 0.15 m.

2. For PHXSource_shockwave_long: Set the Emit Mode to Volume Inject; Smoke to 0.25. Enable the RGB option and set it to brown color (RGB: 123, 94, 64); Motion Vel. to 1.0; Prt Shape to Sphere, custom.; Custom Prt Size to 0.05 m.

From frame 17 to 19, animate the value of Inject Power from 1.0 to 0.0.

Go to Graph Editors/Track View → Curve Editor and check the curve of PHXSource_shockwave_long's Inject Power.

For Inject Power, set the first key frame to Tangents to Fast and the second key frame to Tangents to Slow.

The shockwave is faster and expands to larger scale, so let's extend our Simulator Grid to be slightly bigger. 

Open the Grid rollout and set the following parameters:

With the two shockwave sources in the scene, run the simulation again.

You can now see the two layers of shockwaves: one runs faster and the other slower. All these seven Fire/Smoke sources complete the single explosion.

With this we completed the settings for a single explosion from frame 17. We have added the whole set of Fire/Smoke sources in the scene. Now it's time to simulate all the explosions in the scene.

Since the whole explosion covers a large region, we have to expand the Simulator grid. In order to get a more detailed result we also increase the grid resolution by lowering the Cell Size for the final simulation.

Move the Phoenix FD Simulator to XYZ: [ -22, 0, 0 ].

Open the Grid rollout and set the following values:

Thanks to the Time Base option in the Fire/Smoke source, we can do it in a smarter way.

Set the Time Base to Particle Age instead of Absolute. By doing so, we don't need to set multiple follies of keyframes to the Fire/Smoke. We simply shift-move the keyframes to begin at frame 0. The Fire/Smoke source reads the particle age information from thinkingParticles, so we can have sources emitting fluid procedurally.

Shift-move all the keyframes of every Fire/Smoke Source to the first frame. This table shows the positions of the new keyframes.

With the new position of the keyframes and the Time Base set to Particle Age, run the simulation again.

Everything looks good, but we can add a wind force in the scene for additional realism.

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

Go to the Helpers tab → Phoenix FD and add a Phoenix FD Plain Force. The Plain Force is a simple directional force.

Rotate it so that it points in the positive X direction and set the Strength to 0.5 m. Enablethe Apply Force Behind Icon option.

The exact Position of the Plain Force in the scene is XYZ: [ -28, -1, 18 ].

With the Plain Force in the scene, simulate again.

Now the explosion shifts slightly toward the right as the wind blows.

We are ready for the final render.

The final image is rendered using the V-Ray Frame Buffer with the Color Corrections set to:

Exposure:

• Exposure: -0.37;
• Highlight Burn: 1.00;
• Contrast: 0.14.

Hue / Saturation:

• Saturation: 0.28.

Bloom/Glare Effect is enabled from the Lens Effects panel:

• Size: 30.00;
• Bloom: 0.40;
• Intensity: 1.70.

And here is the final rendered result.