Open Space 4x Windows game

I could definitely use 3d assets.

Either they could be included in the project as unprotected files or packaged so they cannot be opened by others.

If you make contributions to the project I can added you to the credits screen if you want.

Under the OpenSpace4x_Data\StreamingAssets folder are all of the files that get loaded at run time. Technically these files can be edited, but as a best practice there is a mod system to use.

Under OpenSpace4x_Data\StreamingAssets\Mods is a folder named MyMod, which is meant for a starting point to creating a mod. The file structure inside a mod folder is identical as under OpenSpace4x_Data\StreamingAssets, so if you copy the OpenSpace4x_Data\StreamingAssets\Modules into MyMod folder, then changes made to the copied module files will be used instead of the originals.

Audio files must to be .wav or .ogg, texture files must be .png, and anything with the .unity3d extension is a packaged Unity object that cannot be edited, but can be overwritten by another file.

I would say that the economy is most likely going to be comparable to Ages of Empires, where there are a set of resource types, which are collected to be used for construction. Also there is to be a market system for buying and sell resources, and prices change based on how much you buy and sell. Anything that uses resources can also be built by simply using money, but the cost is related to the market value of all of the resources.

Production will work in a similar manner as it does in Stardrive; it determines how long something takes to build.

Food will work like it does in other 4x games, as something required to support populations. If you do not have enough food, then it can be bought from the market, but this will cause the food market price to rise.

The major reason for Unity comes from how easy it is to use compared to Unreal or Cryengine. I'll need to create instructions on how create new game objects and package them, but compared with how other game engine editors work I believe people will be able to learn it easier in the Unity editor.

From a design aspect moving as much data into external text files means that the barrier to modding is just a text editor like notepad or better notepad++.
Edit: This does have a small negative side effect as loading many small files takes longer than loading one big database.

As of right now resources are hardcoded, but their icons, tool tips, and value can be edited by external files. It would require a bit of work, but I could potential create a system where resources are defined in their own files, and there could be an indefinite amount added. Perhaps I would keep the construction resources hardcoded, and allow for infinite numbers of trade resources to be defined externally.

Something I had been think about is growing different foods with farms, and for the most part that would just give different bonuses to the farms like moral or population growth. The defining of resources gives me the idea of being able to define indefinite types of food resources that all get used as your empires food. Different food types could provide tiny bonuses based on their percentage compares to other foods your empire is eating.