Frozen District has shared the third devlog for the House Flipper 2 – Pets DLC. This devlog dives into the science of pet behavior, as voted for by readers of the previous devlog, and how the behavior system works in the DLC.

As usual, the developers began by doing research into how dogs, cats, and rabbits behave when all of their needs are fulfilled. They created behavioral trees to map out the behavioral patterns in diagram form, which helped the team program the pets.

Some behavioral trees grew to be massive in size with several dozen branches of options, especially when elements of randomness needed to be added. In all, the behavioral system in the entirety of the Pets DLC consists of over 3,000 nodes, which represent decision points for the animals.

house flipper 2 pets dlc behavioral tree

Next, a needs-based system was developed by creating a pyramid of needs. This represents the priority of what drives the pets to react or behave in a certain way, not dissimilar to Maslow’s hierarchy of needs. The pyramid in the Pets DLC includes waste relief, rest/sleep, nutrition/hydration, socialization, and fun.

The team decided that each need might grow at different speeds and not necessarily in a linear fashion. Also, other player actions might shape or interrupt behavioral processes.

On top of all of that, the developers gave each pet its own variable animal trait to make it unique and further influence its decision-making. These internal-value traits affect the behavior using systematic calculations. For example, when a dog barks, “if the dog has the Quiet trait and its excitement is above 60/100, there’s a 15% chance it will bark again.”

Evidently, Frozen District has put a lot of work into individualizing the pets and making their behaviors seem as realistic as possible. As a bonus, the team shared a video of a dog that behaves differently depending on where he is petted.