when animating the puppet, the animator holds the chest or waist of the puppet firmly with one hand and change the pose, but at that time it is the core to hold the proportion so that the shape of the puppet does not collapse. If the core is too small or bad shape, the shape of the puppet will collapse when holding it or you can not hold it properly, and other joints you do not want to move will move, animating will be tough.
On the other hand, if the core is too large, the range of motion of the joint will be small and the puppet will not move freely, so you have to think about the optimum shape.
The quality of the core has a big influence on animation, it becomes the same important factor as the armature. You should think about the shape of the core three-dimensionally while looking at the design of the puppet. temporarily assemble the armature and the core and adjust the shape as you look at the state of the movable range. Also, although the strength of the core itself is important, if the armature and the core are not securely fixed, it will be an obstacle to animating. Assemble it sturdy.
Plastic materials or wood are often used as the material, and when the core becomes large, it may be made hollow for weight reduction. Also, when fixing a puppet from the outside with a rod,It is often attached a mechanism to fix the rod to the core.
the core made with wood
It is a core made with balsa. Since it is a puppet for dancing, cutting around the arm so that the arms move freely.
It is the core made with balsa and MDF and cork. Because it is a big doll, so it is made of hard MDF only at the neck bone stab, the back of the head is made of balsa for weight reduction. To fix the eyes and mouth with pins, the front of the head is made of cork so that you can pierce easily.
It is a core made from plastic (resin). I put epoxy putty on the arms and legs so as not to bend other than the joints of the elbow and knee.
On the back is a part glued to fix the rod. Put a brass rod with a diameter of 5 mm and fasten it with a screw from above.