Hi Douglas,
(I have moved this to the Q&A forum, as the Tutorial forum is based on starting a new thread with the Help button below a tutorial to ask questions about the tutorial content.)
There is (to my knowledge) no direct option to convert an Alembic polygon-based animation into a PLA or Point Cache animation; Simultaneously, allow for a tearing process that happens only at the penetration point of the collider object. Alembic is a per frame option (AFAIK), hence the ability to produce new polygons (well, new points and edges) after a tear.
The easiest way to produce a polygon copy is via PoseMorph. Here a single frame (no animation) copy will be the “host,” and the Alembic will be the “point-source”, while the Pose Morph is applied via a Morph-Deformer. This data can then be stored via Cappucino as PLA. (Point Level Animation). This allows disabling the PoseMorph. (file …_01.c4d)
Now we need only to ensure that at the moment, something will tear the fabric apart, the animation date for that part is off, and Cloth/Tear can take over. A Vertex Map is needed here to define the area and timing: Fields are the way to go. (file …_11.c4d)
All the best