Unity-NetCDF

This repository contains some basic C# and Shaderlab scripts for reading and displaying NetCDF data in Unity.

1. How to install Unity

Download Unity Hub from the official Unity website. It is available as a download for Windows, Mac and Linux. Select a version of the Unity Editor (the most recent is fine). Start a new project from the Unity Hub by clicking 'New project' and selecting 3D (Built-In Render Pipeline or Universal 3D.

2. Choose the script you would like to use

Script Name	Description	NetCDF library required?	Custom shader required?
CreateMesh.cs	contains code for generating a variety of simple empty meshes in Unity (ranging from a single triangle to a 3D cube)	N	N
rainbow_cube.cs	contains a function to construct a 3D mesh based on user-defined dimensions, and assign a semi-random RGBA colour to each vertex	N	Y
Wind_Mesh.cs	contains code to read in a remote NetCDF file and plot the horizontal wind field onto a 3D mesh (by assigning the data values to the mesh vertex)	Y	Y
netcdf_mesh_update.cs	contains code to read in a local NetCDF file (user must provide their own), construct a 3D mesh and plot data onto it. This script contains functionality to move forward and backward in time using the keyboard arrow keys. This script was developed using cloud fraction data from a WRF file but can be modified for other types of data.	Y	Y
MultipleFields/wrf_multi_fields.cs	contains code similar to netcdf_mesh_updates.cs but includes additional 'toggle' functionality to switch between different meteorological fields on-the-fly	Y	Y

3. If your script requires NetCDF libraries, here's how you install those (using Windows)

Most of these scripts use third-party libraries to read NetCDF files using C#. These are:

• UCAR's NetCDF-C
• nuget's SDSLite (dependent on NetCDF-C)

Download these packages to your Assets/Plugins folder within your Unity project (if this folder doesn't exist then create it):

4. How to use a custom shader in Unity

Some of the scripts here require the use of a custom colour vertex shader. The file VertexColorShader.shader can be used to create a custom shader in Unity such that an RGBA colour is assigned to a vertex based on its position within a mesh. Save this file into a folder called 'Shaders' within 'Assets' (again, if the folder doesnt' exist, then create it). Then, create a folder called 'Materials' under 'Assets', right-click and create create a new material. Assign the custom shader to the material. Later, when you create a mesh, you will assign this material to the mesh.

5. How to use the scripts

• In the Projects area, navigate to your Assets and save the script(s) into a folder called Scripts (create the folder if it doesn't already exist)
• Double-click on the script in the Project panel to edit as required. You may need to set your default script editor (IDE) in Unity if you have not done this already.
• Create a new object in the Hierarchy panel (by right-clicking, and selecting 'Create Empty')
• Add components to the new object: a mesh filter, a mesh renderer, and a C# script (link to the appropriate script)
• If making use of the custom vertex shader, change the mesh renderer from its default material to the custom material you made earlier
• During these steps, you will see Unity attempt to compile the code. Check the Project/Console section to see if there are any errors in compilation.
• If compilation is successful, hit the 'play' button in the Scene to execute the code.

Example screenshots

Here is a screenshot to show what the output of rainbow_cube.cs should look like if successful:

Here is a screenshot to show what the output of Wind_Mesh.cs should look like if successful (blue = negative velocity, red = positive, white = neutral):

Here is a screenshot to show what the output of netcdf_mesh_update.cs might look like (it will depend on your file!), showing the cloud fraction (where 0 is transparent and 1 is solid white) from a WRF model output file at a particular time frame: