Board Thread:News and Announcements/@comment-26581304-20150906194347/@comment-26871289-20150913173014

First, another data point: I just bred a Rare Furcorn by crossing a regular Furcorn with a Rare Deedge.

It's interesting to ponder how the game decides what monster will result from any given breeding attempt. Generally speaking, I would guess that the program generates a random number and compares that number to a predefined probability table to determine the resulting monster. For example, consider breeding an Enbrat by crossing a Potbelly with a T-Rox. Say the program generates a random number from 1-10 with 1-4 resulting on a Potbelly, 5-8 a T-Rox, and 9-10 an Enbrat. In other words there would be a 40% chance for a Potbelly, 40% for T-Rox, and 20% for Enbrat (just an example, I don't know the really probabilities).

Now suppopse that Rare Enbrat is available. It would be reasonable to guess that there would be 2 successive probability calculations: one to determine the type of monster that results (as above) and one to determine whether the result will be a Rare Enbrat. The question in my mind is which calculation happens first?

It could be that any breeding combo that could result in an Enbrat triggers the Rare calculation to happen first. If the result is determined to be rare, then a Rare Enbrat results and the second calculation is skipped. This approach would produce a consistent probability of a resulting Rare Enbrat across all possible breeding calculations. If the attempt does not result in a rare Enbrat, the issue to consider is how much time the failed attempt will cost. It's readily apparent that Potbellies and T-Roxes would be less costly than a regular Enbrat.

The other approach would be do the Type calculation first and if the result is an Enbrat then do the second calculation to determine whether that Enbrat will be a Rare. Whenever the first calculation generates a Potbelly or T-Rox the result is just wasted time as the 2nd calculation won't be triggered and therefore there's a 0% chance for a Rare Enbrat to result. In this scenario it would actually be better to breed an existing Rare Enbrat against a regular Enbrat. As this combo has a 100% chance to generate an Enbrat, the second calculation to determine whether that Enbrat will be rare will always be triggered.

In short, if you believe the Rare calculation happens first, it's better to breed Potbelly and T-Rox because failed attempts will cost less time on average since some will be either Potbelly or T-Rox rather then the more costly Enbrat. If you believe the Type calculation happens first, then it's better to breed Rare Enbrat and regular Enbrat since that combo has a 100% chance to trigger a chance at a Rare Enbrat.