• Choose a category
• All
• Classic-Fiction

The MassFX tools include everything you need to access the MassFX physics simulation engine. After physical properties are defined, you can define physical forces to act on these objects and simulate the resulting animation. Not only does MassFX make difficult physical motions realistic, but it also is fun to play with.

Understanding Dynamics

Dynamics is a branch of physics that deals with forces and the motions they cause, and regardless of your experience in school, physics is your friend—especially in the world of 3D. Dynamics in Max can automate the creation of animation keys by calculating the position, rotation, and collisions between objects based on physics equations.

Consider the motion of a simple yo-yo. Animating this motion with keys is fairly simple: Set rotation and position keys halfway through the animation and again at the end, and you're finished.

Now think of the forces controlling the yo-yo. Gravity causes the yo-yo to accelerate toward the ground, causing the string to unwind, which makes the yo-yo spin about its axis. When it reaches the end of the string, the rotation reverses and the yo-yo rises. Using Gravity and Motor Space Warps, you can simulate this motion, but setting the keys manually is probably easier for these few objects.

But before you write off dynamics, think of the motion of popcorn popping. With all the pieces involved, setting all the position and rotation keys would take a long time. For this system, using dynamics makes sense.

Dynamic tools let you specify objects to include in a simulation, the forces they interact with, and the objects to be involved in collisions. After the system is defined, the Dynamics utility automatically calculates the movement and collisions of these objects according to the forces involved, and then it sets the keys for you.

New Feature

The MassFX system is new to 3ds Max 2012. •

Note

MassFX isn't the first physic-based system available in Max. Early versions of Max had a Dynamics utility, and recently dynamics were possible using Max's reactor system. These early systems have been replaced by MassFX, which is easier to use and much more robust than earlier versions. •

Using MassFX

The MassFX plug-in was developed by a company named PhysX, which is now part of NVIDIA. MassFX is a complex piece of software with a huge assortment of features that enable you to define physical properties and forces and have the scene automatically generate the resulting animation keys as the objects interact while following the laws of physics.

The MassFX plug-in interface can be accessed from a simple toolbar that's opened using the right-click pop-up menu on any toolbar. The toolbar is named MassFX, shown in Figure 43.1, and it is surprisingly simple, consisting of only five buttons. With the MassFX toolbar, you can open the MassFX Tools dialog box, define objects and constraints to include in the simulation, and control the simulation. The toolbar also includes several flyout tools that are described in Table 43.1.

FIGURE 43.1

Use the MassFX toolbar to open the MassFX Tools dialog box and define and control simulations.

The MassFX commands also are available as menu options in the Animation⇒Simulation–MassFX menu.

The MassFX process

Before getting into the details of MassFX, I want to briefly explain the process involved in using this feature. MassFX works with geometry that is defined with certain physical properties. After these properties are defined, the MassFX engine can take over and determine how all the various objects interact with one another.

The first step is to assign each object to be included in the simulation an object type. These can be either Dynamic, Kinematic, or Static. Dynamic objects are ones that are included in the simulation, Kinematic objects apply forces to the simulation and can be changed to a Dynamic object to interact with other objects, but Static objects don't move and provide the walls and floor