Designing in Zoo Tycoon 2 has been around since 2004, although few designers existed until 2006. Members at ZT Expanded discovered how to open and edit the game's files shortly after the game's release. This has lead to the creation of new animals, objects and others for Zoo Tycoon 2 for other fans to download. While Zoo Tycoon required an official software to create animals, designing for Zoo Tycoon 2 is solely user-supported. Most of Blue Fang, except for BFKeith, haven't said anything of user-made content. BFKeith has stated that he enjoyed seeing what the community comes up with.

ZT2 designing typically improves with the release of each new expansion pack. For example, before the release of Extinct Animals, the only way to make a theropod dinosaur was to shrink the wings of a secretary bird, and model editing dinosaurs was impossible.

How designing works

The game's files are in .z2f format. These files can be opened with WinRAR and extracted from the files to another part of the PC. Once this is complete, files can be edited freely.


This is the most basic part of designing. Mostly, it just involves replacing the name of the original animal with that of the desired animal, but behaviors can be edited as well.

Files involved in coding:

  • .beh - "Behavior". These files control how an animal acts and what it does.
  • .tsk - "Task". These are the tasks that correspond with the coding in the behavior files.
  • .xml - These files are used for a variety of purposes, like the animal's adult and young files, male and female files (if they're different) as well as its Zoopedia article.
  • .trk - "Trick". These files control what tricks marine animals do in shows and are rarely used.

A text editor as simple as Notepad can be used for all of these.

Folders involved in coding:

  • ai - Contains the task and behavior files. It's also the easiest file to find.
  • entities - Contains the animal skins, main uses which control size, star rating, biome and location, folders for eggs (birds and reptiles only) and files for the animal gift. Entities is normally the hardest folder to find.
  • lang - Contains the file for zoopedia.
  • ui - Contains the entry for zoopedia, a use needed to make a new location and several folders associated to the animal gift.
  • locations - Only needed if the animal location isn't in Zoo Tycoon 2. Contains the files needed to make a new location.



Example of a skinned / alpha-edited animal, the w:Dracorex, by lordofworms.

This involves editing the texture files of your animal. An animal's model is laid out in a flat sheet called a "uvw map" or skin. It lists all the animal's body parts. One can either edit the textures of an existing animal or create a new "uvw". Programs typically used to skin are Adobe Photoshop, the GIMP, and Paint, and DXTBmp is used to unlock the images. An animal has a regular skin, a dirty skin, a sick skin, and a sick-and-dirty skin. Skin files are typically in .dds or .tga format, and sometimes in .bmp.

Another recent practice involves editing the "alpha" channel in the skin, which can help add details such as feathers, spines, and other things that are hard to add in the model. However, things such as feathers and spines can only be added if a sufficient mesh exists - one cannot add a spine to Tyrannosaurus unless it's added in 3DS Max or similar.



A very advanced example of a meshed animal, this one being a custom modeled Humbolt squid in a pack called "Crazy Cephalopods".

Meshing is the most recent factor of designing. It originated in late 2006 when fans discovered that it is possible to edit the models in Nifskope, which was previously only used to view them. It is unknown why that term was coined, most likely as it resembles modeling with clay, the "mesh" of an animal.

The first meshed animal was Littlemog's European Unicorn, a user-made unicorn resembling the one from the original game. It was a zebra with a horn. Littlemog then released a tutorial, shortly before Zoo Admin went offline.

One of the very first meshed animals was the African wyvern (a kind of dragon) by Simba, meshed out of a secretary bird. The wyvern was filled with some glitches and bugs, so experienced designers typically discouraged meshing for a long time. Nowadays there are more options to meshing and the Zoo Tycoon Designing Center gives support to it.

There are two types of animal model files: .nif and .bfb. NIFs can be edited, but BFBs are protected, and there's no program that can open them. Even RALCGM, a cheap written program designed to deal with unknown file types, cannot open BFBs. These files use separate files labelled "Materials" to support an animal's texture files.

There has been endless speculation to why Blue Fang converted their NIFs to BFBs in the first place.

An alternate way has arisen to get around the "bfb problem". Some designers, namely Papapanda, have learned how to make entirely new models, and then take out the bone data of the bfb and put it into the new model. This has resulted in creations such as the Papapanda's Ichthyosaurus, the ZTV anniversary animals, the Humpback Whale and Frilled Shark, made by XDS, the giant squid by Legojedij, and the Cuttlefish by Dalturge.

On the other hand, NIFs can be imported into Blender or 3DSMax and edited by vertices. Then it can be exported. The exported file will not work in the game - the shape data must be pasted back onto the original file. That keeps the animal's appearance but keeps the necessary components needed for it to work ingame, although blender has been known to distort models that have the shape data added. There is even a method to edit the NIFs in a viewing program called NifSkope, but that method typically is time-consuming and based largely on guesswork.

See also