cross-posted from: https://lemmy.ml/post/34012299

Background

For those who don’t know, I’m trying to create a FOSS life simulation game — something similar to The Sims.

I haven’t posted updates in !projectharmonia@lemmy.ml about the project for a while, only updates to the related crates I maintain. It’s just me and my wife didn’t have enough motivation to work on it. Mainly because of the overwhelming amount of things we need to make - both assets and code.

Lifesims Are Hard

A life simulation game needs at least one customizable character mesh (which is a huge project on its own), a lot of clothes, animations, textures, and world objects. And coding it isn’t easy either — it’s basically like making 3 games:

1. Life simulation.
2. Building mode.
3. Character creation. It’s probably the smallest part, but still quite complex.

Plus, I’m using Bevy, which is a great engine but still quite immature. This means I have to implement many things myself, even basic features like UI widgets. Some of my work is available as standalone crates: bevy_replicon, bevy_replicon_renet and bevy_enhanced_input. On the bright side, people seem to like them — the input crate is even planned for upstreaming into Bevy. But this also takes time and distracts me from the game.

I guess that’s why we don’t have many life simulation games — they’re quite hard to create even for big companies. For example, Life By You from Paradox got cancelled.

So, is it an impossible task for hobbyists? It would be a shame, because I recently asked which game people would most like to see a FOSS alternative for, and most people voted for The Sims.

A Different Approach

At first, I considered switching to creating a reimplementation that requires the original game assets, like OpenMW or OpenLara. But it’s even harder to implement and for me it’s not as fun as creating something from scratch. So I continued thinking.

When I created bevy_replicon, it originally used bevy_renet under the hood. But it’s not actively maintained, so after each Bevy release, I had to wait a while for it to be updated. Instead of switching to another messaging library, I decided to abstract the messaging layer completely and move the renet-specific logic into a separate crate called bevy_replicon_renet. I documented the API, and people started creating their own integrations. I decided to embrace this strategy by keeping the crate minimalistic but extensible. Now we have a small ecosystem of crates. I think it’s great because more people are getting involved and I have less to maintain.

There also games like Garry’s Mod and Luanti (formerly Minetest). They are basically empty by default and players just install mods that add mechanics, objects, story, etc., all made by the community.

All of this got me thinking: why not create a project like this, but in the life simulation genre? From the game menu, players could download character models, clothes, objects, scripts, etc., created by passionate modders. To avoid downloading each mod individually, I could provide mod lists for one‑click installation. This will significantly reduce the scope of the game. Also, I enjoy creating APIs: even when I lost motivation to work on the game itself, I still actively developed the crates. So developing a game like this should be similar.

I even came up with a name — SimGine, short for “simulation engine.”

During development, I can test things on free assets wrapping them as mods. For example, I can use character meshes and clothes from the awesome MakeHuman. But this could be anything, even a loader for CCs originally made for The Sims games.

As for the game engine, I still think that Bevy is the right choice:

• It uses ECS, which is perfect for parallel simulation of many entities.
• It’s incredebly flexible and modular, kinda in the spirit of the game.
• It’s just fun to use for me. When you making a game as a hobby - it’s very important, otherwise I’ll lose my motivation.

I mentioned that the engine is still immature, but we’re getting there. The upcoming 0.17 release will feature hot reloading and finally adds built-in widgets. Plus, the crates I already made are close to feature-completion.

Project Plans

Right now, I’m planning to wait for the release of Bevy 0.17 and, in the meantime, add a few important features to bevy_replicon. After that, I think I’ll start working on the game. I’ll also start from scratch, since we’ll need a different architecture — though I’ll borrow some of the old code. And this time, I’ll start from the character creator. It’s a smaller part, and if I fail with the rest, at least we’ll still have a cool app for creating digital avatars 😅

Not looking for any collaborators or mod developers yet — I need to create an MVP first. I expect this will take a quite some time. But I would like to hear your opinions about the idea in general.