3DUtrecht

3D Utrecht is a platform ( available at https://3d.utrecht.nl ) where the city of Utrecht can be experienced interactively in 3D using a browser using WebGL technology.

The code of this project is forked from 3DAmsterdam https://github.com/Amsterdam/3DAmsterdam

The main goals are:

• providing information about the city;
• making communication and participation more accessible through visuals;
• viewing and sharing 3D models.

More and more information and data is embedded, allowing future features like running simulations, visualization of solar and wind studies and showing impact of spatial urban changes. It will improve public insight in decision making processes.

Unity (LTS) release only

The project is using the latest LTS (long-term support) release of Unity. We will stick to this version untill new engine feature updates are required for the sake of maximum stability.

WebGL/Universal Render Pipeline

Currently the main target platform is a WebGL(2.0) application. The project is set up to use the Universal Render Pipeline, focussing on high performance for lower end machines. Please note that shaders/materials have specific requirements in order to work in this render pipeline.

Code convention

All the project code and comments should be written in English. Content text is written in Dutch.

For C#/.NET coding conventions please refer to the Microsoft conventions: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/inside-a-program/coding-conventions For variable naming please refer to: https://docs.microsoft.com/en-us/dotnet/standard/design-guidelines/general-naming-conventions

Project Setup

The project consists of two repositories. One is the 3DAmsterdam repository, the other is a city specific repository, in our case this is 3DUtrecht. Unity will use the 3DUtrecht directory to load the project. From the 3DUtrecht project we will use symbolic links to two 3DAmsterdam directories. This way we can reuse code. A symbolic link can be used to act like shortcut to other files or directories. More info on that can be found here

The files structure of the project looks like this.

3DAmsterdam.fork
└───3DAmsterdam
    
3d.utrecht.nl
│   README.md
│   .gitattributes
│   .gitignore
│   sync.py
└───3DNetherlands
    └───Assets
      └───3DAmsterdam
          Config3DAmsterdam_production
      └───3DUtrecht
          Config3DUtrecht
      └───Netherlands3D
      └───WebGLTemplates
          └───Fullscreen3DAmsterdam
          └───Fullscreen3DUtrecht

To setup the file structure the following steps should be performed

1. Fork the 3DAmsterdam repository and checkout to your computer, example c:\development\3damsterdam.fork

2. Setup two origins in your git client for this repository. Name them Amsterdam and Fork. Amsterdam points to https://github.com/Amsterdam/3Damsterdam Fork points to https://github.com/GemeenteUtrecht/3DAmsterdam Every time you want to update your fork to the latest code from 3DAmsterdam, pull it from origin Amsterdam. When you made code changes in this directory you can create a branch and push this Fork. Then you can make a pull request that can be picked up by the 3DAmsterdam development team. This way you can contribute to the opensource project!

3. Checkout code from https://github.com/GemeenteUtrecht/3d.utrecht.nl to for example c:\development\3d.utrecht.nl

4. Add symbolic links as shown below, make sure the drive supports symbolic links. For Windows this only works on NTFS volumes

   (to create the symbolic links you need to open a command prompt and run it as Administrator)

cd \3d.utrecht.nl\3DNetherlands\Assets
mklink /d 3DAmsterdam \3DAmsterdam.fork\3DAmsterdam\Assets\3DAmsterdam
mklink /d Netherlands3D \3DAmsterdam.fork\3DAmsterdam\Assets\Netherlands3D

6. Lastly add the symbolic linked directories in the .gitignore file as follows

3DNetherlands/Assets/3DAmsterdam*
3DNetherlands/Assets/Netherlands3D*

This completes the setup of the file structure. The WebGL directory Fullscreen3DAmsterdam can be copied and made custom

For further documentation check the 3DAmsterdam documentation at https://github.com/Amsterdam/3DAmsterdam/tree/develop/docs

Unity Input System

The project uses the new Unity input system called Input Action Assets. The input mappings are defined in \Assets\Netherlands3D\Input\3DNetherlands.inputactions

This will then generate a c# class that will be used in \Assets\Netherlands3D\Input\ActionHandler.cs

Local Test WebGl build

In order to locally test a build you start your own http server. If you have npm installed you can use the http-server package and run it in the build directory

http.server

Or if you have Python installed you can run

python -m http.server

You also need to install a CORS plugin to make it work

https://microsoftedge.microsoft.com/addons/detail/allow-cors-accesscontro/bhjepjpgngghppolkjdhckmnfphffdag

https://chrome.google.com/webstore/detail/allow-cors-access-control/lhobafahddgcelffkeicbaginigeejlf

Tile System

The platform uses a tile based system consisting of 1km by 1km tiles. The handling of the tiles is initiated by the TileHandler which resides under the /Layers in the scene and needs to be configured with the active Layers that implement the Layer baseclass.

We currently have 4 implemented Layers which are

• Buildings
• Trees
• Sewerage
• Terrain

Each Layer script needs implement the HandleLayer method. This function receives a TileChange variable that provides the RD X and Y coordinate and an action.

The available actions are

• Create (create the tile)
• Upgrade (the Level of detail increases)
• Downgrade (the Level of detail decreases)
• Remove (remove the tile)

AssetBundles

To improve performance the platform uses prebuild assets that are downloaded from the webserver.

To create assets the workflow is as follows

• Generate the assets from code using AssetDatabase.CreateAsset. This will create the asset as text based YAML file
• Then build the asset for WebGL using BuildPipeline.BuildAssetBundles. This will create binary files and needs to be copied to the webserver that will serve them.

Note, the generation these assets can take some time on your computer.

Third parties and licenses

• DXF export library - Lesser General Public Licence

• Sun Script - Credits to Paul Hayes

• 3D BAG - CC-BY licentie (TU Delft)

• BruTile (only used for its Extent struct) - Apache License 2.0

• Simple SJON - MIT License

• Mesh Simplifier - MIT License

• Clipping Triangles - MIT License

• scripts/extentions/ListExtensions.cs - MIT License

• Scripts/RuntimeHandle derivative work - MIT License

• Mesh Combine Wizard - MIT License