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Principles of Modelling

SAE Content Creators

Created on August 25, 2022

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Transcript

PRINCIPLES OF MODELLING

3D FUNDAMENTALS

let's go!

Index

Modelling for Games

Introduction

Topology

Modelling Principles

Take me to the quiz

INTRODUCTION

01

In this session we will look at 3D Modelling Fundamentals. 3D Modelling is the process of creating three dimensional representations of an object or surface within a simulated environment. This practice is best utilised within the Computer Graphic industry for Videogames, Animation, VFX and Film. It does however have considerable application in several adjacent industries for visualisation and logistical purposes such as Architecture, Engineering, Medical Science and Marketing.Models are constructed through creative formation of topology. Topology allows artists to build complex shapes such as characters, vehicles, environments and other CG props that may be required for a project.Understanding how to shape topology through modelling and sculpting techniques is important, but equally important is understanding their significance and relation to the rendering platform's budget.

index

topology

02

3D Models consist of a combination of Vertices, Edges and Polygons.The geometric allignment of these elements are what create a model's Mesh.The topology of a mesh refers to the edge-flow and overall arrangement of polygonal faces created by the vertices and edges within the model. Topology is integral to the functionality of a Mesh within all 3D industries.

Vertices

- Single points within the 3D space.

edges

- The lines that connect 2 Vertices to one another.

polygons

The surfaces created when multiple edges are connected.

index

topology

02

Vertices

edges

polygons

- Single points within the 3D space.

- The lines that connect 2 Vertices to one another.

The surfaces created when multiple edges are connected.

index

topology

02

N-Gon

Quad

Tri

Polygons come in different shapes depending on the number of Vertices and Edges that make them up.- A triangular polygon has exacly 3 vertices and 3 edges. This is the smallest polygonal face.- A square or rectangular polygon is known and a Quadrilateral. It has exactly 4 vertices and 4 edges. These are the preferred type of polygon for games due to the way they naturally subdivide and contort when animated.- An N-Gon is a polygon with more than 4 vertices and edges. This type of topology is typically avoided due to it's geometric properties. They can always be divided in to Tris and Quads but have some unique application of their own in special circumstances.

Tri

quad

N-gon

index

topology

02

Different shapes will require different arrangements and volumes of topology. Typically speaking geometric shapes such as cubes and prisms require less topology due to their straight edges.This is because more topology is required to create a curved edge. This inherently makes organic structures require extra topology resulting in a higher cost of resources.

index

topology

02

240 Polygons

960 Polygons

8 Polygons

12 Polygons

120 Polygons

The number of polygons required to create a mesh is known as its Polycount. Artists will aim to keep their model's polycount within whatever budget it has been allocated.This is due to how resources are dictated within a production's budget and ensure that the final scene will run smoothly within the technical confinements of its platform.

index

modelling for games

03

It is vital to understand the value of Topology and its relation to the CG production.Game Engines and Rendering Programmes require processing power just like any other piece of software. Everything within a scene, whether that be a Video Game, Animation or Simulation has a budget.The budget is dictated by the hardware powering the platform. Better hardware yields a larger budget and therefor more resources available to utilise within the scene. The larger the budget the more resources, such as polygons, become available to the artists. More resources allow artists to create greater and more complex detail within their models.This can often mean a direct correlation between hardware and quality. Hardware improves over time with the evolution of technology meaning that the quality of CG productions will continue to advance also.

index

modelling for games

03

Below are some examples of console platforms from the previous three decades. These systems were considered peak hardware of their time. Mouse over them to see their respective system stats. Notice how considerable the computational capabilities of these machines grows through the years. How do you think this effected the budget of videogame titles released on these platform ?

SNES(1990)CPU: 3.58 MHzRAM: 128kbGPU: 16bit PPU

XBOX ONE(2013)CPU: 1.75GHz OctoRAM: 8GB DDR3GPU: 800MHz

Sony Playstation(1995)CPU: 33.58 MHzRAM 2MBGPU 64bit PPU

Playstation 5(2021)CPU: 3.5GHzOctoRAM: 16Gb DDR6GPU: 1810 MHz

index

modelling for games

03

Metal Gear Solid (Playstation, 1998)
Metal Gear Solid V (PS4, 2015)
Metal Gear (NES, 1987)

Here is an example of the same character developed over 30 years. This gives us an idea of how significant the evolution of technology is to production. Each stage represented above was developed to the capacity of the Hardware available at their time.

index

modelling principles

04

Modelling, like many aspects of CG production, should strive for efficiency and functionality.Efficiency can mean several things when it comes to designing a 3D model. It is important to consider the following criteria before you begin to better guide the design process and budget for your project.

perception

How the model will be percieved in the scene. Which angles will be visible, is it close to camera or far away ? Is it large or small ?

function

What function does the model require? How is it used? Is it a weapon, does it have moving parts ?

frequency

How frequent does it appear? Is this a unique asset in the scene ? Will it be reused in other parts of the project ?

index

modelling principles

04

Knowing how a model will be utilised within a scene can help rationalise the use of high or low polycounts.It is a misconception that higher polycounts are considered inefficient. The reality is that some models require higher volumes of polygons due to their perception, function or frequency. As mentioned previously a model's shape will also dictate this. It is important to remember that topology should aim to be efficient where possible but be allowed to incur costs where doing otherwise would impead the visual quality of the final product. Most CG assets will fall into categories that help define their baseline budget. These can include, but are not limited to:

character

A character within a game will typically demand the highest available budget. This is due to how frequently they appear on camera and function in game.

props

Props can range from small background elements to Hero Assets like feature weapons, interactive elements and objects of significant importance. Their budget varies widely from asset to asset.

environment

Similar to props these can vary in size, significance and repetition. Typically these will be recycled regularly and aim to be as efficient as possible without compromising visual standards.

index

Principles of modelling

QUIZ

Play

Question 1/5

A model consists of the following elements:

Points, Edges and Polygons

Vertices, Edges and Polygons

Vertices, Lines and Faces

Question 2/5

Good job!

An Edge is defined as:

A singular point in 3D Space.

The curvature of a models topology.

The line that connects 2 Vertices together.

Question 3/5

Good job!

A model's polycount is directly related to the project:

Copyright

Budget

Art Director

Question 4/5

Good job!

An artist should consider the following criteria when creating a 3D model:

Perception, Utility and Location

Perception, Function and Frequency

Size, Colour and GPU.

Question 5/5

Good job!

What is the ideal Polycount for a 3D Model ?

Over 1K Polygons

It Depends

Under 1K Polygons

Congratulations!

GAME OVER

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