AutoPhysics Settings

AutoPhysics is a complex tool. Its behavior can be tuned within wide limits using a relatively large set of parameters.

For convenience, these parameters are separated into two tabs. Both can be found on the Scene Settings panel.

Basic Settings

This group controls the main features of the Physics Ghosts. It is available on the AutoPhysics tab.

Fulcrum Area Indent
How much the fulcrum point is increased.
Used in situations when the corresponding parts of the character mesh happen to be bigger than the “default” size of the fulcrum point(s) calculated on the basis of the Point Controllers.

The default value is 5.

Vertical Force Smoothness
This parameter defines how much the vertical (the Y axis) movement of the character is smoothed for the AutoPhysics simulation. The higher this value is, the more linear the trajectory will be.



The same animation with Vertical Force Smoothing set to 50 (up) and to 200 (down).

Set to 20 by default.

Ang. Momentum Smoothness
This setting defines how much the tool smoothes the character’s rotation. The higher its value, the more the character’s poses will be altered to remove distortions of the Angular Momentum value.

The default value is 50.

Ghost offset
These are the three coordinates of the physical assistant rendered in the Viewport window.
The coordinates work in relation to the character’s position, i.e. if all three are set to zero, the position of the physical ghost would coincide with that of the character.

This value can also be adjusted right in the Viewport window.

1. Left-click the assistant to select it.

2. Use the Translate manipulator.

Full cycles
Defines how many times the tool should simulate snapping the character to the AutoPhysics ghost.
Increasing the number of cycles improves the accuracy of the calculation. However, this also slows the tool down.

This parameter can be either set manually or using one of the pre-defined values (1, 2 and 5). The default value is 2.

Advanced Settings

These parameters are intended for fine-tuning the Physical Ghosts’ behavior. They can be found on the AutoPhysics (Advanced) tab.

N Interpolations frames
The number of frames used for smoothly interpolating the objects to the position(s) they should have at a fulcrum point.

This kind of interpolation is necessary because physical simulations are not applied to the character outside of the fulcrum point frames. Instead, only the Center of Mass trajectory is adjusted, and the character moves as a whole. In some situations, this might distort the positions of the limbs, if they end up too far from the corresponding fulcrum points.

To fix this issue, limb positions are additionally interpolated on several frames that precede the fulcrum point.

Minimal interval size
The minimal length (in frames) of the part to subdivide the animation into.

AutoPhysics works by separating the animation into small chunks and calculating how the character should move in every one of them.
This parameter can be either set manually or using one of the pre-defined values (3, 5 and 7). The default value is 5.

Minimal ballistic size
The minimal length of a ballistic interval (in frames).

If the character has no fulcrum points on every frame of an interval longer than specified by this parameter, such an interval is considered ballistic, and ballistics are calculated for it.
This parameter can be either set manually or using one of the pre-defined values (3, 5 and 7). The default value is 3.

Iteration numbers
The number of regular cycles of physics simulation. Does not simulate snapping.

This parameter can be either set manually or using one of the pre-defined values (1, 2 and 5). The default value is 1.

ForceToGravity Max Ratio
The value of the force of gravity is multiplied by this coefficient to determine how fast the force applied to the character can change. If the force exceeds the resulting value, it is filtered by the Y axis.

How much the force is filtered is determined by the Vertical Force Smoothing parameter.
This parameter can be either set manually or using one of the pre-defined values (2, 3 and 5). It is set to 3 by default.

ForceToGravity Min Ratio
Defines the minimal force applied to the character from the fulcrum point, and with it, how fast the character can descend.
The value can range from 0 to 1. If it is equal to 1, the character cannot descend. The closer the value to zero, the higher is the speed of descension. However, decreasing this parameter can sometimes affect the stability of the simulation.

Used for vertical filtering. Set to 0.1 by default.

Shift Position Penalty
This is the penalty for altering the initial position of the character (on the XZ plane).

This parameter can be either set manually or using one of the pre-defined values (1, 10 and 100). Its default value is 1.

Shift Velocity Penalty
Same as above, but applied to the character’s initial velocity.

Can be either set manually or using one of the predefined values (1, 10 and 100). Its default value is 10.

Shift Velocity Max
This parameter limits how much the character’s velocity can be shifted.

The value can be either set manually or using one of the predefined values (1, 10 and 100). Its default value is 100.

Shift velocity is measured in Cascadeur units per frame. This means that scaling the scene up or down might prevent AutoPhysics from solving the given animation.

Shift Position Max
This parameter limits how much the initial position can be shifted.

Measured in Cascadeur units.

Can be either set manually or using one of the predefined values (1, 10 and 100). Its default value is 100.

Stable Interval Threshold
The threshold used for determining whether an interval is stable or not.

This parameter can be either set manually or using one of the pre-defined values (0.01, 0.25 and 1.0). By default, it is set to 0.01.

Use friction constraints
If this is enabled, the horizontal force applied to the character is limited on the basis of the value of the vertical force.

Disabled by default.

Friction Coefficient
Defines the maximum value of the horizontal force applied to the character on the basis of the vertical force.

For example, if this value equals 0.25, the horizontal force cannot be greater than one quarter of the horizontal force.

This parameter can be either set manually or using one of the pre-defined values (0.2, 0.5 and 1.0). Its default value is 0.5.

Filtrate Vertical Force
If this is enabled, the tool will smooth vertical (Y-axis) movements of the character.

Enabled by default.

Filtrate Angular Momentum
If this is enabled, the tool will filtrate the character’s angular momentum.

Enabled by default.

Apply on stable
Defines if the tool should be applied on the stable (non-ballistic) intervals.

Enabled by default.

Apply on ballistic
Defines if the tool should be applied on ballistic intervals.

Enabled by default.

Apply on convex up
If this is enabled, the simulation is applied to the parts where the trajectory of the character’s center of mass has a convex (arching) shape facing upward.

Enabled by default.

Apply on convex down
If this is enabled, the simulation is applied to the parts of the trajectory that have convex shape facing downward.

Enabled by default.

Additional Settings

Several auxiliary settings can be found in the Settings Window.

This group of parameters sets the colors used for AutoPhysics assistant and Timeline intervals:

AutoPhysicsError, AutoPhyscisFrozen, AutoPhysicsNeedChange and AutoPhyscisNoChange define the colors of the assistant.

AutoPhysicsCorrectIntervalColor, AutoPhysicsSolvedIntervalMaxColor, AutoPhyscisSolvedIntervalMinColor, AutoPhysicsUnsolvedIntervalColor and AutoPhysicsWholeIntervalColor define the color used for marking up the Timeline.

Two more parameters can also be found in the same tab:

MaxClampPhysicsTransformRotations limits the number of times an object’s rotation can be changed for the physics simulation.

MaxClampPhysicsTransformTranslations does the same for the object translation.

 

See Also

AutoPhysics

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