In Maya Fur, the distribution of hairs, defined by the fur density that places hairs evenly over all surfaces that have the fur description attached.
When you disable this option, the hairs defined by the fur density are distributed per surface. For example, if you have a fur description with a density of 1000 attached to 10 surfaces and this option is enabled, the 1000 hairs will be distributed evenly across all 10 surfaces. If this option is disabled, each of the 10 surfaces will have 1000 hairs.
