Procedural Grass

Introduction

For a more in-depth technical breakdown check out the posts on my website here

This project was originally inspired by a GDC Presentation by the developers of Ghost of Tsushima. In this GDC video they discuss how they created the visually stunning grass in Ghost of Tsushima. The presentation directed much my approach to the project. I did my best to recreate the effect they made for the game, while also introducing some neat features not included in their approach. Link to presentation here

Overview

The project has two parts: The Grass Generator, which is a Houdini HDA, and the Grass Shader which is a Blueprint in Unreal Engine 5.1. Combining these two together allows users to create unique fields and patches of grass in their Unreal game! This tool will be used in the upcoming USC game, Manas. All together the project took around 100 hours to complete.

Houdini HDA

The Houdini HDA is responsible for all of the grass mesh creation. Using this HDA users are able to create individual bunches or entire fields of grass. You can change the LOD if desired, BUT with Unreal 5.1 these meshes are Nanite enabled!

Unreal Shader

The Unreal Shader determines how the grass you created using the HDA interacts with the environment. From this shader you are able to change the wind level, the color (including blending landscape color onto the grass), whether the player can part it or not, and numerous other features. As mentioned before this project was made in Unreal 5.1, so all the meshes with the shader can be used in the Foliage Brush!