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Requires Phoenix FD 3.12.00 for V-Ray Next and V-Ray Next for Maya Hotfix 1 Official Release for Maya 2015 or newer. You can download 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.

In this tutorial, we guide you through the creation of a fusion effect resulting from the splash of two fluids - milk and chocolate. For this goal, we create two liquid emitters, one for each liquid type. By using a Blend Material, we set the appearance of the mixture.

The two liquids are simulated with different RGB each, and then the grid RGB channel is extracted via a Phoenix Grid Texture and used as a mask for the Blend Material. We use Surface Tension to keep the liquid particles packed together in a smooth mesh and only allow them to break up into larger droplets.

To make the liquid mesh look even smoother, as a real milky-looking liquid, we use the Phoenix smoothing tools found in the Rendering rollout of the Simulator.The Download button below provides you with an archive containing the start and end scenes as a reference.

To download project files:

Want to follow along but don’t have a license?:

Create a regular Poly Plane and set the Width / Height to 23 / 42 respectively.

Extrude it with a Thickness of 1 to give it a volume.

Duplicate emit_geo_milk and rename the copy to emit_geo_chocolate.

If you'd like your setup to be identical to the provided scene files, here are the exact transformations of the emit_geo_chocolate:

Translate: [ -176, 18, 0 ]
Rotate: [ -4 , 37 , -64 ]

Group both objects together by selecting them and pressing Control + G.

Rename the group to emit_geo_grp to keep the scene organized.

Create a Phoenix Liquid Simulator that envelops both source geometry objects - make sure to move it to the origin by zeroing-out the transform values in the Channel box.

Open the Grid rollout and set the Cell Size to 1. The Cell Size parameter is your main control for the resolution of the simulation. The lower this value is, the longer the simulation will take but the more refined the result will be.

The exact values for the X / Y / Z size of the Simulator are [ 420, 45, 55 ].

Hit Start to run the simulation.

Increase the Discharge of both Liquid Sources to 400. The Discharge controls how strong the liquid is pushed in the direction of the geometry normals when the Emit Mode is set to Surface Force.

Select the Simulator and open the Grid rollout.

Enable Adaptive Grid by setting the Adaptive Grid parameter to Temperature/Liquid. This option specifies which simulation channel will be tracked by the Simulator to determine when the size of the grid is to be increased or decreased. Adaptive Grid is a huge time saver - the initial grid is dynamically expanded to accommodate the movement of the fluids, cutting down on both processing time and memory.

Reduce the Threshold value to 0.01. The grid will expand when the content of a cell near a border goes above this value.

If you notice any clipping, you may increase the Extra Margin to a value of 5 - 10. The Extra Margin acts as a 'buffer' area for the Threshold - instead of looking at the cells right at the border, the Adaptive Grid algorithm will look 5 cells deeper within the simulator and expand based on the contents there.

Select Enable Limits. The red box in the screenshot to the right is a preview of the Maximum Bounds for the simulation. Adaptive Grid is a huge time saver - the initial grid is dynamically expanded to accommodate the movement of the fluids, cutting down on both processing time and memory. This will add a few extra voxels at the borders during adaptation.

The exact values for the X / Y / Z limits are X: [ 90 / 90 ] Y: [ 120 / 60 ] Z: [ 100 / 100 ].

Open the Preview rollout and enable Mesh Preview.

Open the Dynamics rollout and set the Steps per Frame to 4.

The Steps per Frame parameter controls how many calculations are made between 2 consecutive frames. This includes the emitters as well. If you see stepping in the emission, as in this example, increasing the SPF is most likely your best option.

Under the Grid rollout, set the Scene Scale to 2. The Scene Scale parameter will affect most of the dynamics in the simulator. A smaller value will produce splashier, more turbulent movement while a larger Scene Scale will give the impression of a heavier, more inert fluid. You may experiment with this parameter but keep in mind that you will also have to adjust the Discharge of the Phoenix Sources as well.

In the Dynamics rollout , reduce Gravity and Time Scale to 0.5.

The Gravity parameter is self-explanatory - the liquid will fall down slower when this value is lower.

Time Scale is very similar to the Steps Per Frame parameter in a sense that it also scales down the velocities in your simulation, thus removing detail from the sim. You should be mindful of this when tweaking your setup.

If you'd like to significantly slow down a liquid simulation, a better approach would be to use the Time Bend Controls section of the Input rollout. We don't make use of these as the RGB channel blending (for slow-down) is not supported at the time of writing this tutorial.

Repeat the same steps for emit_geo_milk.

Assign a new Lambert material to emit_geo_milk and rename it to mat_emit_preview_milk.

Plug a Volume Noise texture in the Diffuse slot of the material.

Dial in the following values for the Volume Noise texture:

Noise Type: Perlin Noise,
Amplitude: 8,
Depth Max: 1,
Frequency: 10,
Scale: 100/100/100,
Disable Effects → Invert

Animate the Translate: Z parameter of the 3d placement nodes for each Volume Noise texture such that it goes from 0 to 100 during frames 0 to 100.

The exact key frames are:

Frame: 0 – Translate Z: 0
Frame: 100 – Translate Z: 100

 Here's the emission when modulated by the animated Volume Noise texture.

Because the fluid is behaving like pure water at the moment, we tweak the Viscosity and Surface Tension parameters to give it some thickness.

Set Liquid → Surface Tension to 0.5. The Surface Tension parametercontrols the force produced along the curvature of the liquid surface - this keeps the liquid from breaking into individual particles when a force is applied to it.

Set the Droplet Breakup to 1.0, with a Droplet Radius of 2.5 cells. The Droplet Breakup balances between the liquid forming tendrils or droplets. Larger values will produce more droplets.

Droplet Radius controls the radius of the droplets formed by the Droplet Breakup parameter (in voxels). Therefore, if you increase the resolution of the grid, you should also increase the Droplet Radius.

Set Viscosity to 0.01. Viscosity emulates thickness - the higher this value is, the more the liquid will resemble thick mud, honey or tar.

Add a new Deform → Non-Linear → Bend deformer to emit_geo_chocolate.

Set the Curvature to 10.

If you'd like your setup to be identical, do the following steps:

1. Parent the bend handle to emit_geo_chocolate.
2. Set the Rotate values to (90, 0, - 90).

Enable the emission of RGB on phoenix_source_chocolate and set the RGB Color to White (255, 255, 255).

Enable the emission of RGB on phoenix_source_milk and set the RGB Color to Black (0, 0, 0).

Select the Simulator and enable the export of the RGB and Velocity Grid channels from the Output rollout.

Doing this will tell Phoenix to store the information for those channels in the cache files on disk.

The Velocity channel is required when rendering the simulation with Motion Blur.

The RGB channel we need for a mask for the Blend Material used for the final render.

We first create our Fill Light.

Add a V-Ray Dome light to the scene.

Set the Color Mode to Temperature, and the Temperature parameter to 5000 to give the lighting a warm tint.

Set the Options → Invisible to Enabled so the dome light is not visible in the final image.

To give the Key Light a softer emission pattern, enable Use Rect. Tex and plug a VRay Softbox texture in the Rect. Tex slot.

Enable Base → Tint On.

Enable Hot Spot / Dark Spot → On.

Enable Hot Spot / Dark Spot → Tint On.

Enable U and V Vignette and set the Horizontal and Vertical Gradient Color Ramps to go from black to white.

Let's create the Chocolate material.

Assign a V-Ray Material to the Phoenix Simulator and rename it to mat_chocolate.

Set the following settings:

Diffuse Color: 0.094, 0.031, 0.012
BRDF Type: Phong
Reflection Color: 0.431 , 0.290, 0.223
Reflection gloss: 0.75
Refl. Max Depth: 10
Refraction color: 0.200, 0.063, 0.020
Refraction gloss: 0.75
Refr. Max Depth: 10

Here's a rendered image of the blend material.

The only thing left to do is to add a Rim light and a background for the final image.

Let's add a Rim Light.

Create a Sphere Light and transform it to Translate: [ -15, 46, -178].

Set the Light Color to RGB: [ 0.551, 0.372, 0.293 ].

Set the Intensity Multiplier to 5.

The Radius is set to 112.

Options → Invisible is enabled so the light is not visible in the final image.

Add a Poly Plane with a Width/Height of 1800/800.

Move it to [ 0, 0, -325 ] and Rotate it to [ 90, 0, 0 ] so it's facing the camera.

Assign a new V-Ray material and set the Diffuse Color to RGB: [ 0.09, 0.09, 0.09 ].