eXtendedRealities| Lecture 2 foundations of 3d

2023/11/08 eXtendedRealities 共 2674 字,约 8 分钟
Buliangzhang

Introduction

design,blueprints, 3D modelling, game engine, VR/XR

Part 1 Softwave Types

3D asset creation tools can be further categorised one of 4 groups:

  • Modelling 简单的景物
  • Animation: rigging and skinning
  • Sculpting: 复杂的provide more advanced features to sculpt models and produce various texture maps
  • Rendering – For generating image or video (usually built into 3D modelling software and available as plugin too
  • Texturing: (covered later in the course) for adding realism to assets and the 3D environments

    Modelling Tools

  • 3D Studio Max, Maya, Blender: Digital media production,Modelling and Animation,Game asset development;
  • Solidadge: engineers
  • Sketchup: modelling and design
  • Revit: architects and construction industy

    Sculpting Tools

    zbrush mudbox

    Posing and Animation Tools

    Daz Studio, Valve’s Source : Character animation, Character posing

    Rendering Tools

    renderman

    Texturing Tools

    substance painter

    Game Engines

    procedural generation

    Part 2 3D Terminologies

==What is a 3D model comprised of ?== Ploygons 就是面cube have 6 ploygons Ploygons are made from edges and vertices:edges, vertices, face

2D Square vs 3D Cube

WireFrame game engine like triangles

Primitives基元

3D environments are just mathematical constructs. Every 3D space has dimensions The most basic 3D shapes are called Primitives. ![[3107a700453d52d94693141e31d9e4e.png]]

Polygon

Recap - a polygon is a many-sided shape which has a set of vertices and edges FBX is used as an export to game engine

Triangles are always Convex

Concave polygons are often difficult to process Simple linear equations Any polygon can be decomposed into triangles; triangle shape

How many vertices, edges, & triangles to make a cube? • 8 vertices • 18 edges • 12 triangles

3D Graphics Data Representation

Vertex coordinates list, polygon table and (maybe) edge table

Part 3 3D Modeling and Communication

3D objects 3 axis objects need to have volumn the structure and poly count vertices

Volume: Values and emotions

Shpere : cute and friendly Cube: Strong and Sturdy Pyramid: Fast and aggressive

Realism :

Anatomical Geographical Structure Mathematical (Mandelbox) Particles Mechanical

Part4 Computer Modeling Principles and Techniques for XR

Modelling Approach

Top-down Bottom-Up Made up of triangles ![[09f12b1993611fe94a85b461bd76467.png]]

Primitives

2-D primitives include: rectangles, circles, triangles, and other polygons. 3-D primitives include: blocks, cylinders, prisms, spheres, and cones.

Top-Down Modelling Boolean Operations

Boolean operations - combinations of geometric entities: add, subtract, intersect, divide, glue, and overlap, etc.

Boolean CSG operations

Union Intersection Difference

Quads

quads is for the modelling process easier to sub-divide the model if you use quads

Bottom-Up Modelling

Open Spline Close Spline

Joining Splines

You can join 2 or more splines together using Boolean operation.

Ngons

a polygon with more than four vertices and edges should be avoided Sometimes modelling with Ngons is quicker – but always avoid it!

Low vs High Poly

Low poly challenges: retopology or decimation the details from high poly can be baked into texture maps

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