fabioden

Enforce

Added 2022-06-15 23:04:20 +0000 UTC

Enforce is a plugin that allows you to apply "forces" or "movements" to different body parts.

Each force will be applied and also parented to the joint where it is used, this is useful, because when we change the person's pose the forces will remain the same relative to their joint even if the position is different. However, sometimes forces that make sense in one pose may need to be modified in another, or replaced.

The plugin allows users to add, modify and delete forces in real time over all people in the scene, making it a very useful companion to Pose Manager. Anyway, you can use it to add additional movement to any existing mocap.

Mode of use

The procedure is very simple:

Select a pose with Pose Manager or load some mocap.
Select a person, and a joint in the plugin
Add a precise or a random force to that joint

After this press Play and modify the force to your taste. You can add new ones, modify them, and delete those you don't like.

Selecting the target

In the upper part of the plugin you can choose the person to whom you want to apply a force, activate Target Person for this, and then select the part of the body where you want to apply the force by activating Target Joint.

For a quick setup you can also use the Next Person button to quickly cycle between the people in the scene and there are 3 buttons for common joints: head, chest, and hip. You can have one force activated per joint.

Creating new forces

Forces are created by using the Precise Force and Random Force buttons.

Random Force is a force completely out of control, you can apply it when you want incontrolable "chaos" in a certain place.

Precise force creates a force where its parameters are fixed and you can then modify them to your liking.

Controlling the "playback"

The buttons to control the forces are self-explanatory, Play activates all created forces, Stop stops them, Delete deletes the currently selected force, and Delete All will delete all of them.

Modifying the forces

The Modify Force button allows you to modify the parameters of a precise force, there are 4 parameters which I think are the most important:

Force Factor : defines the maximum distance that the joint or any part of the body can move from its current location. To prevent the parts from "getting out" of the places where they have to be in, it always starts at 150 value, which is a low number.
Force quickness : defines how fast the joint moves in the direction defined by the force.
Cycle Period : defines how long it takes for the joint to make a "full movement" back and forth. Personally I like to start at about 0.90 which is a "slow" movement and manually lower it to make it faster.
Torque Factor : Causes the joint to "twist" a bit as the force moves the joint. It can give realism applied to the hip, for example, but if we want the movement to be completely straight, we have to give it a value of zero.

Modifying precise forces over time

With this feature you can make the precise forces variable over time. It is activated through the Randomize Forces menu, where you select how often you want the forces to be modified: 5 seconds, 10 seconds, and Variable, which is indeterminate variable time decided by the plugin itself. You can disable this feature again by choosing the Disabled menu item.

Try the following test: set Randomize Forces to Variable, create a precise force, press Play, and then press Modify Force. You will see how the force sliders move by themselves and change their value from time to time.

The checkboxes on the right, the ones that start with Random like Random Force Factor, Random Torque Factor, etc, allow you to define which parameters are variable over time and which are not. These checkboxes can only be modified when we have Randomize Forces in Disabled mode.

Avoiding "decoupling" error with Randomize Forces ON

There is one parameter that gets extra attention and that is the Force Factor parameter, which defines the maximum distance that a force can move. If we make this parameter too high it can cause things to "get out" of others, I think I'm being clear about what I mean.

Due to this I have taken some precautions. Switch Randomize Forces to Disabled mode for a second and perform the following:

Start with the default value of 150 from any precise force, click on Modify and start to increase its value to the point close to "getting out". Return to the plugin and press Update Max Force Factor, this will keep the force below this value so disconnections will not happen after we activate Randomize Forces again.
For convenience I have also added its minimum value so values too small to the point where nothing moves are avoided. Repeat the process, and press Update Min Force Factor this time.