Using Particles to Transform Objects

You can use particles to transform objects. This is similar to particle instances, but actual scene objects get transformed instead of instances of master objects.

Objects are matched to particle IDs by selection order. If there are more objects than particles, then some objects are not transformed. Conversely if there are more particles than objects, some particles do not get an object attached to them.

Under the hood, a null named xform_container_pointcloud is added to the scene, and used to build and store an array of transformations corresponding to the points’ position, orientation, and scaling. The objects are added to a group called KinematicsGroup, and each object gets an ICE tree that reads a transformation from the array on the null and uses it to set Note that adding objects to the group later will not set their transforms — you must reattach the objects to the particles instead.

Attaching Objects to Particles

1. Select the objects to transform in order, starting with the object that you want to be transformed by the first particle. Alternatively, you can select a group, in which case the order in which the objects were added to the group is used.

2. Choose Kinematics > Create > Transform Objects by Particles from the ICE toolbar.

3. Pick the point cloud to use.

Reattaching Objects to Particles

To modify the set of objects that get transformed by particles, or to change the order, simply repeat the procedure for attaching them.

Note that previously attached but currently unselected objects are not affected, so they are still attached to the particles that they were originally attached to. This means that you might have two or more objects attached to the same particle unless you detach them manually.

Each time you reattach objects to a pointcloud, a new xform_container_pointcloud null and KinematicsGroup are created. You can delete the old ones manually if they are no longer being used.

Detaching Objects from Particles

1. Select the objects to detach from the particles. If you select a group, use Select > Select Components/Members to select the objects themselves.

2. Choose Kinematics > Create > Remove Particles Constraint from the ICE toolbar.

Note that the xform_container_pointcloud null and KinematicsGroup are not removed. You can delete them manually if desired.

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