Geometry - Introduction 

Triangle and Polygon Usage

Level of Detail

Additional Geometry Best Practices

Demo: Level of Detail

This project will highlight optimizations for 3D models that can make a game more efficient while maintaining aesthetic intent, improving the performance and experience on mobile devices. 

Geometry

Course Introduction

The Optimization Process

Profiling Tools

Textures - Introduction

Texture Size, Color Space, and Compression

Texture Atlases

Texture Filtering

Mipmapping

UV Unwrap, Visual Impact, and Texture Channel Packing

Alpha Channels and Normal Map Best Practices

Editing Texture Settings

Demo: Texture Atlases

Shaders and Materials - Overview

Optimizing Shaders for Mobile Platforms

Transparencies

Additional Material and Shader Best Practices

Demo: Draw Calls and SRP Batcher

Lighting - Overview

Light Modes and Types

Lighting for Static Objects

Light Probes

Shadows

Demo: Baked Lighting

Conclusion/Next Steps

Welcome to 3D Art Optimization for Mobile Applications! In this introductory project, we will review the course's main learning objectives, discuss the practice of optimization, and identify the optimization tools available at your disposal.

Introduction/Optimization and Profiling

This project will highlight the different implementation considerations and optimizations that take advantage of a Texture’s flexibility. When given the correct settings and applied correctly over their many use cases, Textures play a major role in achieving your desired visual effects. 

Textures

Shaders and Materials play a crucial role in determining how target hardware will process and render your 3D objects. In this project, you will explore best practices that will keep the shaders lightweight and fast when running on phones with limited resources.

Shaders and Materials

Lighting is one of the most important aspects of real-time 3D visuals. It can set the mood, guide interactions, and identify goals and objectives. In this project, you will learn about and compare the differences between the available lights and light modes that you can use in your 3D mobile application.

Lighting

ARMUnityMobileOptimization.zip

In this intermediate course, participants will learn how to produce performance-optimized 3D assets and scenes for mobile applications. Topics will cover tips on optimizing Geometry, Textures, Materials, Shaders, and Lighting. This course was created with technical artists and content creators in mind.

Arm & Unity Presents: 3D Art Optimization for Mobile Applications

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Overview

When Not to Use LODs

Why Use LOD

An Appropriate Number Of Triangles

Number of LOD Levels

Creating LOD Meshes

Conclusion

In this tutorial, you will learn about the different use cases in which Level of Detail (LOD) can help highlight details in your 3D models at varying distances while optimizing application performance.

Level of Detail (LOD) allows you to control the number of vertices that are rendered for each object in your Scene depending on the object’s distance from the camera. Doing this will improve your application’s performance.

LOD also avoids the micro triangles problem discussed in the last tutorial for distant objects. We recommend that you optimize the LOD for every 3D object whose distance from the camera changes while the application is running.

The following image shows how you can use LOD management to reduce a 3D model’s complexity while retaining an appropriate level of detail as the model moves away from the camera:

Here are some key things to remember when using LOD:

Keep in mind how triangles affect the silhouette of an object when you are reducing triangle counts.

Mipmaps, which are functionally LOD for Textures, should be used with your models. We will cover mipmaps later in the Textures project.

LOD can also apply to Shader complexity. The Shader and Material can be optimized for 3D objects that are farther away. For example, you can reduce the number of Textures an object uses as it moves farther from the camera.

LOD is not suitable in every situation. For example, avoid using it in an application where both the camera view and objects are static, or where the object is already using a low polygon count.

LOD comes with a memory overhead and a larger file size because Mesh data must be saved so it can be used in real-time.

The following image shows a Scene where LOD is not used because the Scene is static. In this situation, you can use other optimization tricks, such as removing polygons that aren’t visible to the player:

As an object moves away from the camera, its detail becomes less visible. From 20 meters away, it’s hard to see any difference between an object with 200 triangles and an object with 2,000 triangles. Since you don’t want to use more triangles than your Scene requires, using LOD is a great way to optimize your application with little noticeable impact..

A boost in performance, as fewer triangles must be processed.

LOD helps mitigate problems that micro triangles cause.

The following image shows how distant objects look the same, even with different polygon counts:

Here are some key points to keep in mind when using LOD:

It’s often worth reducing the number of triangles between each LOD level by 50 percent.

Don’t use dense areas of triangles on objects with a lower LOD. These are only visible when the object is close.

Check what the LOD looks like at different distances from the camera. Lower LOD means a lower resolution when viewed up close, but that's OK for objects that are farther from the camera.

The following image shows how an object looks when the polygon count drops by 50 percent for each level: 

The following image shows the lower LOD object up close. It looks less detailed but its appearance is acceptable when it’s farther from the camera:  

If you don’t reduce the polygon count enough on lower LOD objects, your application’s performance will be negatively impacted. This is because the GPU is processing more vertices than needed.

But if you are too aggressive in reducing the polygon count for lower LOD objects, then the object’s details will pop in and out of view in real time. This could potentially ruin the experience for the user. 

There is no predetermined number of LODs that an object should have. It depends on the size and importance of the object. For example, a character in an action or a car in a racing game can benefit from using more LOD levels than a small background object like a tree.

If you use too few LOD levels, you won’t benefit from a gain in performance. And, if there is too large a jump in polygon reduction between levels, then the popping that happens during an LOD switch will be more noticeable. If you use too many LOD levels, your application’s performance will be impacted. 

Also, memory usage increases with more LODs, as you must store the extra Meshes somewhere, resulting in a larger file size. But the largest cost is your time, especially if you’re creating each level by hand.

When creating LOD Meshes by hand using 3D software, either remove edge loops or reduce the number of vertices on the object. While this gives you more control, it can take longer to complete.

When creating LOD Meshes automatically, use a built-in modifier or separate LOD-generation software. Examples of built-in modifiers include ProOptimizer in 3ds Max and the Generate LOD Meshes function in Maya.

Using LOD Meshes is a smart way to optimize your application by minimizing excess geometry on objects that change distance from the camera. In the next tutorial, we’ll explore some additional best practices for optimizing geometry for mobile applications. 

Level of Detail

1. Overview

2. When Not to Use LODs

3. Why Use LOD

4. An Appropriate Number Of Triangles

5. Number of LOD Levels

6. Creating LOD Meshes

7. Conclusion

Complete this tutorial