Gonna be honest here, I've worked on this for so long, so many iterations, lots of versions for each 3D part, software and all, at this point I just wanted to publish everything I had and do it fast. And you are totally right, publishing without parametric source files was a mistake, I'll upload everything I have shortly, prices included. Note: mice require smaller setups and that just leads to the redesign of most parts - smaller ball, ball driver, lever with weaker springs... training cats prompts for a larger ball, same issue. VR setups for cats though would be super cool!

On this setup my rats were only habituated, they did not end up playing Doom. Even habituation seamed super slow, they were a year old when I started it. On the previous setup though, when they learnt to run on the ball and how that influences their reward, they got hooked. I believe they enjoy not just the reward, they get a sense of how their actions influence the game and they like that. They would run on the ball so much at some point they wouldn't even bother drinking all the juice and it was just dripping on the setup.

No idea what they would best like to play. It needs to be a first person game though, that's what they are able to understand how to handle, it's more natural to them.

Thank you for taking the time to give feedback! I also hope pet VRs become a thing and people can connect with their pets virtually too!

Oh, I hope you don't take this as me being upset. I'm super happy and totally get the motivation. I a fan of the adage "better to do something half assed than no assed" (not that this is half-assed). Just wanted to make the comment to help drive motivation and let you know there's a demand. Releasing the sources could really help too just so people don't have to work with the mesh.

But on the rat part, that is super interesting! I was suspecting they might not like Doom because shooting a gun might be such a foreign concept to them that it breaks immersion. But it seems like you say they like running around in the simulated environment? (Time for Cheeze-Doom? lol)

Again, super cool and thank for releasing things! This is that crazy stuff I just love to see people exploring.

Thank you! <3 On shooting: exactly that, it is so foreign to them, I doubt they could grasp the concept, but they can understand the loop of: pull lever -> audiovisual feedback of shooting with monster disappearing -> reward. Biting or scratching a surface as a form of attack may work better, but the audiovisual + reward response should help them to understand at what visual signals to pull the lever to make it go boom.

This mod includes collecting cheese (though it's a side activity, and maybe too subtle for the rats): https://youtu.be/qPRvw6kRN-8?si=j9iuTuiHerm0AhQ2

And here's a thing I knew had to exist: a doom mod/level set on a moon made of cheese... https://youtu.be/XxdeUbE9kvw?si=_cpJQKuDy87BN7EP&t=10m20s

They missed a real opportunity for "Omelette Doom Fromage" there

But yeah, I'd wager too subtle. I'm also questioning now how much rats use smell for navigating their environments. I notice that my cat is a lot more smell oriented than I initially thought and I think it makes a big difference. Hard to tell though.

Humans are /extremely/ visual compared to other animals: this tends to make us underestimate the intelligence of other animals (when we use visual intelligence as a proxy for general intelligence) and miss out on smart uses of other senses entirely. Rats are well-known for thwarting maze studies using things like fine sensitivity to slope, directional orientation using smell gradients across a room, or detecting the direction of researchers outside the maze based on micro-vibrations.

(Good book on the general topic of measuring animal intelligence: "Are We Smart Enough to Know How Smart Animals Are?" by Frans de Waal)

Is the graphics rendering modified to output actual barrel projection to match the display, or did you just take the original perspective projection and stick it on a distorted screen?

Consider making the screen panoramic around a larger radius rather than just around the head, perhaps on the order of ball diameter. This reduces the visual stereodisparity mismatch and lowers the cognitive load for habituation.

Consider also making the trigger chin- or bite-activated to allow simultaneous shooting and moving.

Anecdotally: Cats like fruit ninja.

Funny enough, so does my green cheek conure (small parrot about the side of a fist). Their beaks are made from keratin, like our nails, so it's conductive when touching the screen.

The hiss of the bombs gets him a bit angry though. Parrots hiss and it kind of sounds like that.