Trouble modding animal spawn rate

[_Georgia_]

Hi, I've never made a mod before so I've probably run into a really silly and obvious problem that I can't overcome.

I want to increase the spawn rate for some animals and started with deer. I've increased the spawn and herd number in `deer.json` file to an absurd degree in all their and I don't see any changes to their spawn rate. Can anyone help me with this? I've attached what I've got so far. this file is the only place I can see anything to do with deer spawns so unsure what I've missed.

increaseAnimalSpawn.zip

 

[StarFeather]

I'm having a similar problem, but I want to stop animals from spawning altogether. Changing all the spawn values to 0 did absolutely nothing, they keep spawning normally as if my code isn't being applied at all. Hopefully someone can help us.

[xXx_Ape_xXx]

@_Georgia_

Hi and welcome to the forums!

 

Had a look at your mod, and there's a couple of ways you can approach this, to achieve what you wish.

Firstly, your folder structure inside your zip file, is wrong. It should look something like this:

yourmodv1.0.0.zip/
├── assets/
│   └── yourmodid/
│       ├── blocktypes/
│       │   └── new blocks you want to add to the game here
│       ├── itemtypes/
│       │   └── new items you want to add here
│       ├── lang/
│       │   └── en.json    - languagefile for things your mod adds
│       ├── patches/
│       │   └── patch files should be in here
│       ├── shapes/
│       │   └── shape files you want to add here
│       └── textures/
│           └── new textures you want to use here
├── modinfo.json
└── modicon.png

 

Secondly, you've edited the original json files and want to use those to replace the vanilla ones. Not recommended practice, but can be done.

This is possible by placing them inside the same folder structure you found them, inside the "game/" folder in your mod .zip file, like this:

yourmodv1.0.0.zip/
├── assets/
│   ├── yourmodid/
│   └── game/
│       └── entities/
│           └── land/
│               └── hooved/
│                   ├── deer.json
│                   ├── goat.json
│                   └── moose.json
├── modinfo.json
└── modicon.png

 

Last, I had a look at the spawning and numbers, and found that changing the value in "maxQuantity" didn't really do much for the amount of animals spawning.

However, changing the values in "groupSize" had a huge impact on the amount spawning. This can be changed both for worldgen and runtime, where worldgen is used when a new chunk is generated and tries to spawn animals, while runtime is used in an already generated chunk and the game tries to repopulate the animals (ex. after you've killed everything in the area)

 

I hope that makes some sense, and helps you on  your way to create your mod. If you need more help, don't be afraid to ask! You'd get faster answers on the discord, if that's an option 

 

Edited June 26, 2025 by xXx_Ape_xXx

[_Georgia_]

@xXx_Ape_xXx thank you!!!!
I did think that discord might be the best place to go but didn't want to pester there if it wasn't. I'll go there next time I have questions

By the way, would the recommended approach for this mod be with a patch?

[xXx_Ape_xXx]

@_Georgia_

Yes, I would do these changes with a patch 

 

And don't be afraid to post questions on discord, there are no dumb or annoying questions!

Edited June 29, 2025 by xXx_Ape_xXx