An asset is a combination of one or more textured 3D models plus some parameters, which together define the look and properties of a ploppable, growable, or network element. Every unique building or element will require its own asset. Abandoned and derelict buildings may be designated with a standardized asset or by creating a simple variant of each relevant asset (with, e.g., boarded windows). Construction may be depicted using either a collection of standardized animations or by creating a custom animation for each asset.
Standard assets are those included with the game. Although the code for Charm Cities is open-source, most standard assets beyond the bare minimum required to test the gameplay are specifically excluded from the open-source license. Thus each standard asset must include an extremely simple 3D model (e.g. a flat-colored cube of the correct size) as a fallback for people building the open-source variant.
This allows the game to be saleable while still keeping the benefits of an open-source license.
Custom assets are those created by users after the game is released, which may be released under the user's choice of license. Users should be able to create custom assets using a similar workflow to the asset creation in Cities: Skylines, so that players of both games can easily create assets that work well in both.
Standard Asset Guidelines
Community members are welcome to create standard assets on spec with the understanding that they will be credited (regardless of whether the asset is used in the final game) and that the Charm Cities project reserves the right to edit or exclude the asset to maintain a consistent style across the project. As with all issues regarding finances and project style, issues of compensation and of which assets are used will be discussed openly and transparently in the community Discord before final decisions are made. All work done for Charm Cities will be paid if the game shows a profit.
Because we want to allow members of other game modder communities to port their work to Charm Cities with minimal effort, we are keeping most of the conventions of other games, particularly Cities: Skylines. In particular, Charm Cities uses the same eight-meter (26 foot) square grid. Size your buildings as accurately as possible. Unlike previous city-builders, we are aiming to have city buildings scaled fairly realistically relative to one another.
Standard assets should be provided to the project in the form of .blend files, with three separate meshes provided:
- the original, high-poly mesh with all original PBR textures
- a simplified mesh (1000-5000 triangles) with textures baked onto the 1024x1024 texture maps listed below
- a low-poly (~100 triangle) LOD model with textures baked onto the 128x128 texture maps listed below
- an extremely simple primitive model (e.g. one or two cubes) with flat colors, to be included as a fallback in the GitHub repository for testing
Provide the following texture maps:
- base color
- ambient occlusion (optional)
- metalness (optional)
- emission (optional)
Give every asset a name and brief description. If your asset is intended to fit a specific architectural style, please note that. Be sure you specify how you want to be credited.
Currently desired assets
Assets we can use in the immediate future include:
- Phase One:
- Growable residential buildings, any density, any architectural style. Any lot size between 1x1 and 4x4 tiles is welcome, but 2x2 and 4x4 are highest priority. For size reference, a 4x4 lot is about a quarter-acre or a tenth of a hectare.
- Phase Two:
- Growable commercial buildings, specifically those selling food and clothing, any architectural style. Any lot size between 1x1 and 4x4 tiles.
- Growable light or heavy industry, any industry, any architectural style. Any lot size between 1x1 and 4x4 tiles.
- A collection of ploppables for a small municipal water supply system such as would be found in a small town with no surface water (as in the Midwestern United States). Only one such asset is needed, and you will need to research to find accurate sizing and reference photos, so do not begin work until you have approval.
- pump house for a municipal well
- water treatment plant
- water tower
- wastewater treatment plant
- wastewater injection well
- A small ploppable medical building on a 4x4 lot, any architectural stype. Only one such asset is needed, so do not begin work until you have approval.