Advanced

Do not fear the advanced tab.

Environment

Scale

The most important parameter for the simulation is scene scale. Since Rodeo works with real world physics it is quite a difference if it interprets you scene units as meters or centimeters. When you add the first object in the setup tab of Rodeo it will assume that it fits within a cubic meter and adjust the scale accordingly. You need to adjust this value if the first object was much larger or much smaller as a cubic meter. For example, to scale an Ubershape cube of 100x100x100 EI units to a the size of a die, enter for scale: 100 EI units = 0.01 meters.

Note: Rodeo will error when a triangle of your object is smaller as 0.001 units. If you detect such error you will need to either increase the objects scale or make an approximated object and replace it with the problematic one.

Gravity

Gravity is the main force that will let objects move into a certain direction. The gravity of earth is 9.81 m/s per second downward, -Y in EIAS. Increasing this value to -20 for example will make things fall down faster. However, you will have no "feeling" anymore for what happens with the objects like say a die. Setting the gravity to (0,0,0) will simulate zero gravity as in space. The gravity is available as a socket channel which can be animated in the Project Window of Animator or be modified using Xpressionist.

Smoothness

max Correction Velocity

The physics engine will apply velocities when collisions happen. You can limit the maximum velocity applied to an object with the max Correction Velocity. Too high values will cause objects to suddenly fly off. Too low values might cause collisions to produce object penetrations. The Infinity checkbox disables the limit set in the value entry filed.

Global Error Correction

The Global Error Correction will determine how much of the simulation error is corrected from one frame to the next. An error occurs if one object penetrates another during collision. A Global Error Correction value of 100% will correct also the slightest penetration of objects. This can cause tremendous forces to avoid interpenetrations and may result in your objects flying off. A value of 20-80% is recommended.

Global CFM

is a setting that makes the simulation softer.

Auto Disable

The auto disable options will remove objects from the simulation that move very little for a period of time. For example, a cube that has come to rest after falling on a plane needs no further computation until it is hit by a moving object.

Velocity Threshold

The velocity threshold will remove an object from the simulation when its velocity is lower as this value. However it may happen that the object is just in an unstable position waiting to fall down, like a child on a swing before it swings downward again. To compensate for this you can also set a Timeout value.

Timeout

Timeout sets the time range in frames in which Rodeo will still calculate an objects movement eventhough it is already lower as the Velocity Threshold.

Always Enabled

To get a simulation running and bypass the Velocity Threshold and the Timeout value in the starting phase of the simulation you can set the Always Enabled value. If its set to 10 for example the first 10 frames starting with the Startframe set in the Solver Timing will force a calculation of all velocities for all objects. This value can also be misused to force all objects to be enabled enabled during the entire simulation by setting its value to the value of the Endframe.

Solver Timing

Startframe and Endframe

Startframe and Endframe mark the start and end of the physics simulation. When starting at frame 0 the physics controlled objects start out at rest. You can give objects an initial velocity by animating these objects from frame 0 to frame 1, and setting startframe to 1. This applies to linear velocity and to rotational velocity. You can also set the Startframe to a later time if you have already simulated an animation but want to introduce other objects at a later time to the simulation. The startframe can temporarily be overwritten with the Tweak From Here button. Please refer to the Solver tab for an explanation of the Tweak From Here button.

Solve during Preview

This option is important if you have objects that change their shape over time. In this case Rodeo needs to sample the geometry for every frame of the simulation. To be able to do so you need to set this option and run a preview in Animator. Rodeo will than solve the simulation while the preview is running and be able to sample the dynamic geometry on every frame. Also refer to "Static Geometry" in the Meshes tab.

Accuracy
allowed Penetration

Here the sensibility of the physics engine can be adjusted. The engine has been overworked and tweaked so that no penetrations need to be allowed.

allowed Link Violation

Links must have some loose to run smooth which can be adjusted here.

min Subframes

Rodeo calculates the object motion also inbetween two frames to be able to get correct results if this value is set to a higher value than 1. For example, a cube can fall "through" a plane because on one frame is it above the plane while on the next frame the cube is already beneath the plane. To enable Rodeo to see what happens inbetween these two frames it needs to calculate subframes. If Rodeo is missing collisions this value must be increased. 10 subframes is the default.

max Subframes

The simulation can have tough moments for the physics engine. That is when there are severe object collisions that violate the allowed Penetration and the allowed Link Violations settings. Rodeo will than start to increase the subframes to get a correct solution. This can tremendously slow down the simulation. To limit the time to compute the solution we impose a maximum number of steps between two frames for the engine. We risk an imperfect simulation by doing this. Increasing the max Subframes value will in general yield better results.

CG Solver

The CG solver is an alternative to the default solver. It yields more exact solutions than the default solver (within the same number of iterations), but might introduce instability with objects that use limited joints.

Max Collisions Per Object-Object

A minimum of 20 is recommended. This effects only mesh-mesh collisions (not boxes or spheres). The finer the mesh, the more collisions are required to keep the meshes seperate.