A) Default Condition:
When the condition is Default then the shipment is split irrespective of any attribute. Example: If an order has 4 products then the shipment is split into 4 different shipments no matter what attribute is chosen.

B) Split if attribute exists:
When we enable this option, shipment splits only if any product contains a selected attribute. If an attribute is assigned to any of the product and now we choose to place an order by adding the product having assigned attribute and along with that some other products, then our shipment will be split according to the number of products present in the order placed.

Like, if we have 6 products in an order out of which two products have assigned attributes then shipment will split in 6 different orders having different order ids. If none of the products in the order have the chosen attribute associated with them then the shipment won’t split at all.

Like, in our previous example if none of the product out of 6 products has the desired attribute associated with them then there will be a single shipment having all the 6 products.

C) Split according to attribute:
In this condition products having the same attribute will be clubbed into a single shipment and different shipments will be created for different attributes also the products that do not have the chosen attribute associated with them will be clubbed into a single shipment.

Like, if an order has 6 products out of which 2 products have desired attribute associated to them and rest four have no desired attribute, so now the shipment will be split into 2 different shipments, one having products with desired attribute and one having products without the desired attribute.