Utility panel > reactor > Preview and Animation rollout > Preview Animation button
Menu bar > reactor > Preview Animation
reactor toolbar > Preview Animation button
It's useful to be able to preview reactor simulations from within 3ds Max. The Preview Window lets you view and interact with a simulation in real time. You can run the simulation, interact with the objects in the scene using the mouse, and even update your objects in 3ds Max with their current state in the preview.
To preview a simulation in the Preview Window:
-
If no errors are found in your current scene setup, the Preview Window opens with your scene.
-
Press P to start the simulation.
At any time during the simulation, you can orbit around the scene by left-button dragging the mouse within the Preview Window. With Havok 1 and Havok 3, you can pan the window by middle-button dragging; with Havok 3, you can also pan the window by right-button dragging.
To interact with objects in the Preview Window :
-
Position the mouse cursor over the object you want to interact with, and then press and hold the right mouse button (Havok 1) or the Spacebar (Havok 3).
This creates a reactor spring between the mouse cursor and your chosen object.
-
While holding the right mouse button (Havok 1) or the Spacebar (Havok 3), move the mouse.
This drags the object, letting you pull it around, unless it's a fixed object, or attached to one, and interact with other objects in the scene.
-
To release the object, release the right mouse button (Havok 1) or the Spacebar (Havok 3).
To update 3ds Max from the Preview Window:
At the bottom of the window, profiling and timing information is shown :
-
The current time step (simulation step) used for the simulation. This value is initially taken from the Preview & Animation rollout but can also be changed by using the Performance menu.
-
The number of substeps used for the simulation. Again, this value is initially taken from the Preview & Animation rollout but can also be changed by using the Performance menu.
-
The current simulation time; that is, the time that the current image in the preview represents in the final animation.
During the preview, reactor tries to run the simulation in real time. In other words, if a simulation step of one second takes only 0.7 second of CPU to simulate, reactor "waits" 0.3 second before simulating the next step. That way, the animation is presented in the window at the same speed as the final animation in 3ds Max.
However, for complex scenes or slow CPUs, simulating a particular period of time can take actually more CPU time than the specified period. For example, a simulation step of one second might actually take two seconds to calculate. In that case, it is not possible to present the animation in real time, and the animation is therefore presented during the preview at a slower speed that the final animation will have once it has been created. When this happens, the preview reports it by appending an asterisk (*) to the current time:
Play/Pause (P)—Starts and pauses the simulation. If the simulation is paused, the display remains active and you can still pan, rotate, and zoom the camera, but the physics world remains still.
Reset (R)—Resets the simulation, returning objects to their initial positions.
Important: When About rollout > Choose Solver is set to Havok 3, only Camera Settings is available from this menu.
Camera Settings—Opens a dialog that allows you to specify the near and far clipping planes for the camera, and to change the camera’s field of view (F.O.V.). The clipping planes can also be set externally from the reactor utility Display rollout.
Faces—When on, the faces (and not the edges) of the display bodies are rendered.
Wireframe—When on, the edges (and not the faces) of the display bodies are rendered.
Sim Edges—When on, the edges of the physically simulated geometry (the simulation geometry for each body) are rendered in the preview window. This is useful for seeing what’s physically happening in a simulation.
Grid—When on, three 2D grids are displayed in the XY, YZ and ZX planes.
Origin—When on, the X (in red), Y (in green) and Z (in blue) axis are displayed at the origin (0,0,0).
Flashlight On/Off—When on, a flashlight located behind the camera lights the scene. When off, lights defined on the Display rollout of the utility are used. If no lights are defined, the preview uses a single fixed light.
Fixed Step (60,50,40,30 fps)—Choosing one of these options changes the frequency of the simulation to the given value; a frequency of 30 fps yields a time step of 1/30 (0.0666) second, 50 fps means a time step of 1/50 (0.02) second, etc.
Substeps (1-100 substeps)—Choosing of these options sets the number of substeps taken in every simulation step.
This menu is available only when using the Havok 1 engine.
Pick at C.O.M.—During the preview, you can pick and drag objects (see To interact with objects in the Preview Window :. A spring is the attached between the mouse cursor in the screen and the object. When this option is on, the spring is attached to the center of mass of the object. Otherwise the spring is attached to the point on the object where you first right-clicked.
Mouse Help—This option shows some help regarding the use of the mouse to control the camera and mouse picking.
Update MAX—Takes the position and rotation of the objects in the simulation and uses them to update the objects in 3ds Max.
Use MAX parameters—Resets the substeps and time step (FPS) values to the values set in the reactor utility's Preview and Animation rollout.
The Display rollout of the reactor utility lets you configure various display options for the Preview Window, including cameras and lighting. For more information, see Display Rollout.