Published 4 years ago
Building Life, Block by Block.
We are Katapult, the studio behind CHKN, now in Early Access on Steam. It's an open-world sandbox game where the player creates living creatures. We knew it would be a difficult task to make a creature creating game, and we had a few design goals in mind when starting this ambitious project.


First, since the entire experience revolved around creature creating, it had to be super easy and fun to use. Secondly, and similarly, we wanted the player to have as much control as possible when building. This meant no pre-canned animations.
Third, we wanted creatures to be unique and different from other creatures visually.  A chicken should look different from a giraffe.
And finally, we wanted to add as much emotion to these creatures so that the player could build a meaningful connection.


To solve the creature creating conundrum, we decided that all creature bodies would be made of blocks. This was done intentionally to limit the complexity. By removing complex spatial relations with the use of cubes, players can focus solely on their creation and enjoy the method of building as much as the creature itself.
Next, to give these cubes life, we had to create a procedural animation system. We attempted a ton of solutions for legs and bones to get the creatures moving naturally while still maintaining freedom, but things got weird pretty fast.
Still, there's something about those "chickens" above. Notice how you can’t stop watching them? We wanted players to feel that same intrigue and bewilderment, but have the parts still move as you would expect them to, like this familiar puppy playing fetch below.
Our eventual solution was to write our own; a mix of IK, FK, and frame animation. Even though our creatures were made of blocks, the animation system empowering them created a style that didn't look rigid and created unique fluid silhouettes.
To make each creature unique and really get across different emotions we then added accessories. This broke out of the block rule and gave a lot more personality to the art and game. Where full physics implementation was out of the question due to CPU restraints, we were now able to come up with our own system where physics were applied to accessories that absolutely needed it. What absolutely needs it? Things that jiggle! Octopus tentacles, doggy tails, floppy ears, etc. Just another way to make these blocks a bit more life-like.
And the final sprinkle of emotion came with the eyes. We wanted to have detailed eyes with depth and expressiveness. Players should be able to look at them and actually see how the creature is feeling, and in turn feel something. Creature eyes therefore have pupils, irises, depth and a gleam to them, and are round to be more life-like, something that wouldn't have been possible using traditional cubes.


Now, after cranking out hundreds of lifeblocks, Kevin and Ashley (our artists) have developed a streamlined process for translating real-life creatures to CHKN.
First, they study videos and photos of the animal they're creating before sketching out a 2D version of the animal, with some swatches of real-life textures (fur, skin, teeth, hooves, etc.). They also break down the animal into its lifeblock parts.
Fig. 6 Cow concept. How about them utters?
Then they sculpt the lifeblocks in Maya and create detailed textures using ZBrush and node-based algorithms with substance designer, also adding structural details like wrinkles or fur for realism. (Fun fact: the crab body uses textures from a 1987 Impala!) Finally, they rig and animate all the moving parts.
Fig. 6 Venus fly trap animation.
Fig. 7 Final Venus Fly Trap, in game.
The lifeblocks are then added to the game and thus, a creature is born.


It took a bit of time to find a look and process that felt good, but it's come together rather well and we've found a nice rhythm. We like to think of it as "Frankensteining": take creatures from real life, break them apart, and then put them back together in a way that's unique but also still familiar to players.
Fig. 8 (Rendered) Elephant, CHKNized.
We plan to expand our library of creatures every month, as well as add more worlds and structures. You can subscribe to our newsletter to stay up to date with our production if you like. (And if you have crazy ideas for what Ashley and Kevin should make next, you're always welcome on our Steam forum!)
Kate Howley