Setup

The basic setup of a Rodeo simulation is done in the setup tab. To the right there is a list with all objects that are currently available in your project. From Rodeos point of view an object can have three conditions:

• active physics controlled
• passive or user animated
• invisible


To the left we see an OpenGL preview.

Active physics controlled objects

Each object listed in Rodeos object list has a checkbox as well as a green triangle to set similar to the object flags in the Project Window of Animator. To make an object physics controlled, click the checkmark and make sure the arrow right to the checkmark is green. The checkmark means, that this object is visible for the plugin. The green triangle means that the motion of this object will be calculated by Rodeo (make sure that the object is also animatable in the project window of Animator).

checkboxes

You can select more than one object via SHIFT-select and enable physics for all selected objects with one click.

Automatic shape recognition

Rodeo will automatically detect whether the object is a box or a sphere. If the object was successfully detected as a box its icon changes to a green box in the list. A detected sphere is represented by a green sphere. The physics engine ODE has optimized internal representations for these shapes. That is, working with an internal perfect sphere yields better results than withe the polygonal approximation of a sphere. Objects that are neither boxes nor spheres are displayed as grey spheres.

Dimension

When you select a physics controlled object, the object will get highlighted with its green bounding box in the OpenGL preview to the left. Also the parameters shown below the preview are updated. Object dimensions are the dimensions of its bounding box. These dimensions have to "make sense". Think of a similar situation in reality. Especially think of the relation of the objects dimensions to the height it is falling from. A dice falling from 10cm takes a fraction of a second until it hits the ground and reacts quite different from the equivalently big box falling from 10m which will take some time. You are able to change this overall scale in the Advanced tab discussed later.

Volume

If the object is closed (not necessarily welded) the objects volume will be calculated and shown here.

Density

The density of an object determines how much mass an object has based on its material with the formula volume * density = mass. There are different predefined materials for your objects to choose from the popup menu.

Mass

If the "Mass = Volume * Density" checkbox is checked, Rodeo will automatically calculate the mass of an object according to its volume and density. If the checkbox is not checked you can type in the mass and the density will change.

Friction

Surface friction determines the objects behavior when sliding along other objects. Shiny glass will have a lower friction as rough rubber.

Bouncyness

Bouncyness determines how much force an object will loose when it bounces off a collision surface. A perfect bounce does not take away any force while absorbing bounce will take away all force as soon as an object hits another. Note that theses setting interact between active and passive objects. If you have a sphere that absorbs the bouncing force it will nevertheless bounce of a collision surface if the surface has another value than 0 for the bouncyness. Imagine a marble sphere falling onto a surface of rubber. The sphere absorbs all bouncing forces, while the rubber introduces the forces again to the sphere.

It is possible to shift-select more than one object in the list and change the properties for all selected objects at once.

Passive and user animated objects

Passive objects are all objects that will be used for the calculation of collisions but not be animated by Rodeo. They are static. Nevertheless they will also add/subtract force to active objects based on their friction and bouncyness settings.

A special case of passive objects are user animated objects. As the name indicates they are animated by the user in Animator. Their position and rotation is taken into account when doing the physics simulation. User animated objects are not affected by other objects in the scene. This can cause severe forces. For example, a physics controlled object squeezed between user controlled objects will be likely to fly off with a great velocity suddenly.

The parameters (density, mass, friction and bouncyness) of a passive or user animated object are set the same like for active physics controlled objects.

Invisible Objects

All other objects that are neither marked as physics controlled nor passive or user animated are ignored by the physics engine. Their checkmark is off.