Page History

This page provides a tutorial on creating an Exploding Water Balloon simulation in 3ds Max. 

Overview

...

...

...

...

...

Units Setup

...

Cloth Preparation

...

...

Section
Column width 40% To represent a balloon, we we need geometry with topology suitable for cloth simulations. Create a Geosphere primitive with 30 segments and set its Radius to 20cm. Column width 60%

 

...

 

Section
Column width 40% Apply a ProOptimize modifier on the geosphere. Set the Vertex% value to around 28 to produce a topological pattern suitable for cloth simulations. Column width 60%

...

Section
Column width 40% Set the animation Frame Rate to FPS: 120. By doing so, we can simulate the cloth in slow motion and speed it up after baking. Column width 60%

 

Cloth Simulation

...

...

Section

Column width 40% Reduce the Step parameter to 0.008 or you will get a warning that the Step cannot be greater than frame length. The frame length at 120 FPS is 0.0083(3). Increase the Scene Scale by setting the cm/unit parameter to 10. This parameter can be used to easily control the "apparent" weight of the balloon. From the Simulation Parameters rollout, set Subsample to about 10 - 20. Higher Subsample values prevent the cloth from over-stretching. Enable Self Collision to prevent the cloth from intersecting with itself.   Perform a local simulation to allow the balloon to form an initial resting position, as shown on the image. Click Simulate Local. Once the balloon is in the desired shape, we can do a simulation over time. Column width 60%

...

Section
Column width 40% Congratulations! Once the simulation is complete, you can change the Frame Rate back to NTSC.   Column width 60%

 

...

 

 

 

Section
Column width 100%

 

...

Section
Column width 40% Note The following operation cannot be reverted! Consider saving a backup file first!   Under the Cloth modifier, click the Create Keys button. This creates vertex animation keys and essentially bakes the cloth simulation. Column width 60%

 

...

 

Section
Column width 40% From the Time Configuration window, click the Re-scale Time button. Set the Length parameter to 50 to speed up the animation playback. Column width 60%

PhoenixFD Phoenix FD Liquid Simulation

...

...

Section
Column width 100% Again, make sure the system units are set up correctly (1 Unit = 1 cm).

Scene Setup

...

...

Section
Column width 40% The following image shows the overall configuration of the scene.  Column width 60%

...

Section
Column width 40% Since the simulated balloon geometry has no thickness, we can't use it as-is in the PhoenixFD Phoenix FD simulation. Apply a Shell modifier to the balloon and set Outer Amount to 0.1 cm. This value can be modified depending on the size of the balloon object and the resolution of the PhoenixFD Phoenix FD simulation. Column width 60%

...

Section
Column width 40% Create a LiquidSrc helper from the Helperstab of the Command Panel of PhoenixFD Phoenix FD. Add the Geosphere as an emitter with the Add button.   Column width 60%

...

Section
Column width 40% Create a VRayPhysicalCamera V-Ray Physical Camera and set the settings based on your needs. Enable Depth of Field and Motion Blur. Set the F-Number, Shutter Speed and ISO. Column width 60%

Simulator Properties

...

...

Section

Column width 40% Create a Liquid Simulator from the PhoenixFD Phoenix FD toolbar or the PhoenixFD Phoenix FD menu of the Create panel. Adjust its size so that it encompasses the balloon geometry and try to align it to the camera. The Cell size parameter does not have to be excessively small during the RnD stage - you can set it to 0.3 cm. Enable Adaptive Grid and configure the range of Maximum Expansion for X, Y and Z as shown in the picture. Notice that the back of the balloon is partially outside of the simulation grid. This way we can save some resources and reduce the required memory for the simulation. The back side is pretty much irrelevant considering the camera angle. Column width 60%

...

Section
Column width 40% Once happy with the result, increase the grid resolution by reducing the Cell Size. Set the Cell size to around 0.2 cm. Run the final simulation. Column width 60%

 

Materials and Lighting

...

...

Section
Column width 40% The lighting in the tutorial scene includes a V-Ray Dome light with HDRI assigned. Optionally, you can place a plane in the background and set its color close to black. Column width 60%

 

Balloon Material

...

...

Section

Column width 40% As balloons are usually made of thin rubber and thin rubber tends to be translucent, enable Translucency. Set the type to Hybrid model and the Back-side color to a value slightly darker than the Diffuse color. Adjust the Light multiplier until you're happy with the result. Reflection is set to White as rubber is a dielectric and those usually reflect in grayscale as opposed to metals, which have colored reflections. Refraction is set to a mid-gray value, required for the Translucency effect. Set Fog Color accordingly and try different values of the Fog Bias, until the result suits you. Both of those affect the appearance of the object when Translucency is enabled. Column width 60%

Water Material

...

...

Section

Column width 40% The Index of Refraction (IOR) of real water is approximately 1.33. Set it accordingly. The Reflection and Refraction colors are set to white, which is physically correct. If you want to create a material for a different type of liquid, check the Wine Glass Explosion tutorial (and more specifically - the Material Setup section), where the Fog color is used to create a transluscent translucent liquid. Column width 60%

Extra: Instantaneous Burst Simulation

...

...

Troubleshooting

...