May 13th, 2018

Procedural Generation

Unite 2016 - The Power of Procedural Meshes

Unity Talk by Alexander Birke

Youtube Link to Talk
Suggested Reading:

“Essential Mathematics for Games – A Programmers Guide” by James M. Van Verth & Lars M. Bishop

Links to examples to learn about procedural generation of meshes
Notes from talk:
    Why use procedural meshes?
  • Player Made Content (Ex. Spore)
  • Unique Mechanics (Ex. Gish)
  • Procedural Generation (Ex. Sir You're Being Hunted)
Unity Procedural Meshes
  • Mesh starts by creating vertices, and then making triangles from those vertices
  • Components Needed:
    • MeshFilter - stores the mesh
    • MeshRenderer - shows the mesh
    • Script - to generate the mesh
  • Normal vectors used to determine surface orientation
  • Colors
    • Used to be determined by assigning values to vertices
    • Can be used to provide more information to vertices still
    • Can be done as bytes or floats
    • Bytes generally better
  • UVs
    • 2d coordinates for each vertex
    • Used to map textures
    • Create vector2d array to assign to mesh object
  • Setting Trangle Indices
    • Most difficult part
    • Find common features of topology that repeats
    • Draw it out to help find these patterns!
  • Delaunay Triangulation
    • Maximizes angle of all angles of triangles in triangulation
    • Good for GPU rendering since skinny triangles can lead to visual artifacts
    • Port of triangle.net can be found in an above link
  • Debugging Procedural Meshes
    • Very important to do
    • Use Gizmos and Debug classes
    • Rotate camera to check if tris are facing correct direction
    • Turn on wireframe rendering
  • Optimizing Meshes
    • StaticBatchingUtility: batches multiple game objects together into fewer drawcalls but where each can still be culled
    • Mesh.CombineMeshes: Puts many meshes into one, good if individual meshes not likely to cull, but can break things if not done carefully
  • Optimizing Dynamic Meshes
    • Mesh.MarkDynamic: allocates a memory buffer of sorts to designated mesh to let graphics API know mesh data will change often
    • Base data structure to store data in is flat arrays when possible
    • Lists can be used too, especially if you are unsure how many vertices you will need before creating mesh
    • Frustrum Culling
    • Skinned Meshes
  • Multithreaded Mesh Generation: Unity API not thread safe
  • Compute Shaders
    • GPU great for running parallel tasks
    • Only available on modern platforms: PS4, Xbone, DirectX 11, OpenGL 4.3, OpenGL ES 3.1
    • Unity can cross compile with these options
Summary

Procedurally generating a mesh starts with creating vertices, and then triangles from these vertices. Normals and UVs can be added to this data for more informed meshes. In Unity, your mesh will need a MeshFilter and MeshRenderer component. Debugging your mesh is important, and some tools in Unity to help with that are the gizmo and debug classes, moving the camera around, and turning on wireframe rendering. There are also several options to look into to either optimize your existing meshes how they are, or compute them more efficiently.

More to Research
  • Bezier Curves: parametric mathematical curves used commonly in generating computer graphics
  • Use of GPU to do parallel calculations, and how to connect that with Unity scripting
  • Thread and Multithread Mesh Generation: Not sure what this actually meant
  • Computing shaders
  • Talk through Unity by "Sir You're Being Hunted" on 3D Mesh Generation

Comments

Post a Comment

Popular posts from this blog

Online Multiplayer Networking Solution Tutorial Using Unity and Mirror - Tutorial by: Jason Weimann

February 2, 2021 Networking Online Multiplayer Unity & Mirror Title: Let's build a 4-Player Networked Game LIVE - Online Shooter (with Mirror & Unity) By: Jason Weimann Youtube - Tutorial Description: Intro to using Mirror for networking online multiplayer play in Unity development. Introduction This tutorial has Jason Weimann implementing online network play into a basic Unity twin-stick shooting game. They use Mirror, which is a Unity asset used for simplifying the online network synchronization process. This is a live implementation where they work through many errors transferring a game from simply working locally to working with a host/client relationship. Mirror Mirror - Home Page Mirror is "a high level Networking API for Unity, supporting different low level Transports" (from Mirror themselves). It is a clean solution for implementing a quick and simple online networking option for Unity projects. The core components breakd
Read more

Sebastian Lague A* Tutorial Series - Path Smoothing - Pt. 08 and Pt. 09

December 13, 2019 A* Tutorial Series A* Pathfinding (E08: path smoothing 1/2) A* Pathfinding (E08: path smoothing 1/2) Link - Tutorial 1 By: Sebastian Lague A* Tutorial Series A* Pathfinding (E09: path smoothing 2/2) A* Pathfinding (E09: path smoothing 2/2) Link - Tutorial 2 By: Sebastian Lague A* Pathfinding (E08: path smoothing 1/2) Intro: These tutorials both covered the same general topic of smoothing the path of the unit. Theory Currently the units follow the path by making a straight line from one point to the next, which looks unnatural. To remedy this, they suggest a path smoothing technique. This system starts with each point having a small line pointing directly to the previous point, whose length is called the "turn distance". This line then has a perpendicular line emanating from the end, called the "turn boundary". Once the unit passes this turn boundary, it will start to turn towards the next point in the path (inste
Read more

Exporting FBX from Houdini with Color

April 17, 2019 Exporting From Houdini FBX and Color Information Exporting the Model Using my balloon Houdini example from class, I was able to export the geometry using the Educational version (the Apprentice version does not allow exporting FBX, but you could export an OBJ for my purposes possibly). This was very straight forward, as you can just use File -> Export -> FBX in Houdini. Since I was doing this for a class to use in a Snapchat filter (using LensStudio), I wanted to reduce the poly count a lot. I opened the FBX in Maya and used a basic Reduce to reduce the poly count a lot before exporting that for use in LensStudio. While this was good enough to export the geometry, I could not get any of the color information to come with it. I originally exported out an OBJ and had the same issue, so I exported FBX in hopes it would keep the color information somehow, but this was not the case. Exporting the Color Information My first thought to get the color
Read more