7.10. Joint — Joint class for creating a skeleton

The Joint class can be used to create articulated characters. Bones are implicitely created by linking two joints, i.e. a bone is assumed between a joint and each of its children joints. A Joint object corresponds to a ball joint that has three rotational degrees of freedom. The actual joint is always located at the pivot point of the Joint object and rotates about the pivot frame axes.

If you want your local coordinate frame to be oriented differently, it is not enough to set the offset transform as this will also readjust the local frame so that the effect is actually cancelled out and you will still rotate about the same axes as before. To initialize the new frame you have to call freezePivot() after setting the offset transform. This will set the current offset transform as the new default pose where all angles are 0 and will make the joint rotate about the new axes. After freezing you may want to set the offset transform back to the identity so that the local coordinate frame and the offset frame coincide again. This won’t affect the rotation of the joint but the location of its children (as setting the offset transform on a Joint object also modifies its local coordinate system). But it actually depends on the situation whether you have to reset the offset transform or not.

Rotating a joint is not done by setting its rot attribute but by setting its three individual angles (anglex, angley, anglez).

class Joint(name = "", radius = 0.05, rotationorder = "xyz")

name is the name of the joint.

radius is the radius of the visual representation of the joint/bone.

rotationorder determines the order of rotation about the individual axes.

A Joint has the following slots:

Slot Type Access Description
anglex_slot float rw Angle around x axis
angley_slot float rw Angle around y axis
anglez_slot float rw Angle around z axis

Rotation angle (in degrees) about the local x axis.


Rotation angle (in degrees) about the local y axis.


Rotation angle (in degrees) about the local z axis.


Make the current pivot coordinate system the default pose. After calling this method, the current rotation of the pivot coordinate system will define the default pose. This means, rotations are now defined around the local pivot axes.

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7.9. Group — Group object

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7.11. TargetCamera — Target camera

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