Business and Computing Deanery

3D Modelling Week 3

Advanced modelling

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Aims of today Discuss your presentation Advanced modelling

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Last week Software Modelling concepts

Polygon Spline Patch Parametric

3D parametric modelling Primitives Transformations Aligning Cloning Modifying primitives Boolean

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Plan your model Massing model? Use a graphic or scan? Set up your grid Set up a file/folder system

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Sketch or Storyboard

Adventure Gamers : Dreamfall: from sketch to 3D model (2005)

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Accuracy Imagine a pen How would you model it? Now look at a real pen

Details make a big difference Practice to be imperfect

Why?

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References Using reference materials will

improve the quality of your model Build a reference library

The object itself Photographs Drawings Video

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2D One method of creating a complex

3D object Convert the lines into 3D objects Visualise and define cross-sections Proper scale

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2D to 3D - Extrusion

3ds max v7

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2D to 3D - Lathing Create a path Choose an axis

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2D to 3D – Sweep or Loft Create a 2D shape Create a path Cap or close the ends? 3ds max v7

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2D to 3D - Skin Create a number of cross-sections Skin them

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Activity Draw a 2D shape and extrude it Create another 2D shape and lath it Create a 2D shape, a path and

create a loft Find out how to do a skin

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File formats for modelling Portable or universal file format

DXF .dxf Drawing Interchange Format Widely used in CAD (Computer Aided

Design) OBJ .obj

Computer animation an visual effects

Native May be converted 3ds max .max

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Exporting/importing files File conversion

3D Studio (3DS) Adobe Illustrator (AI) ASC Scene Export (ASE) AutoCAD (DWG) AutoCAD (DXF) Shockwave 3D FiLMBOX (FBX) Initial Graphics Exchange Standard (IGES) Lightscape Material (ATR) Lightscape Blocks (BLK) Lightscape Parameter (DF) Lightscape Layers (LAY) Lightscape View (VW) Lightscape Preparation File (LP) Stereolithography (STL) VRML97 (WRL)

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Edges Real objects rarely have a sharp

edge Bevel or chamfer Radius Fillet

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Surface Modelling More free form than geometric

(parametric) modelling. A subdivision surface is a surface that

has been divided into more faces while retaining the object's general shape

Subdivision adds more detail to an object, or to smooth it out

Use modifier stack to “collapse” a parametric model to some form of editable surface.

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Why surface modelling? Great flexibility in modelling Game engines expect a mesh

Default model type During rendering polygons are ‘smoothed

out’ Meshes allow the optimisation of models

Reduce the number of faces Low polygon modelling

Reduce rendering time Key part of successful production

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Mesh objects Early versions of Max used triangles

All faces were coplanar Good for the rendering engine

Over time rendering engines have been modified

Polygon modelling without subdivision More efficient Eliminated extra edges More control over the polygon object

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Meshes Triangles

Vertex Edge Face

Polygons Vertex Edge Border Polygon Element

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Mesh or poly - which to use?History lesson Initially Max only supported mesh

objects Subdividing the mesh into triangular faces

ensured that all faces were coplanar Guaranteed to render well

Over time rendering engines have been modified to handle polygons Makes the model more efficient Eliminates all the extra edges required to

triangulate the mesh Murdock K.L. (2005)

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Tessellation Subdivides the faces of the object

into two or more: Polygons

or Triangles

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Converting to editable objects Use the Quad

menu Or

Right click the object in the Modifier Stack

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Editing a polygon model Convert an object into a editable

polygon Removes all parametric controls,

including the creation parameters If a modifier has been applied to an

object you need to use the Collapse All command first Combines the stack operations Cannot undo, save a backup file

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Editable Mesh Surface Polygon mesh

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Edit face Faces provide the renderable

surface of an object.

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Extrude Soft selection Extrude Bevel

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Activity Make a crown

Create a tube Convert to an editable mesh Extrude polygons

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Soft selection The Soft Selection

controls allow you to partially select sub-objects in the vicinity of an explicit selection

This causes the explicit selection to behave as if surrounded by a "magnetic field"

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Working with vertices Select one or more vertices Magnetic of soft selection

Use for transforms of vertices The program applies a spline curve

deformation to unselected vertices surrounding the transformed selected sub-object

A magnet-like effect with a sphere of influence around the transformation

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Activity Create a sphere

Convert to an editible polygon Push and pull vertices to make a face

Not easy!

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Edit Edge An edge is a line,

visible or invisible, forming the side of a face and connecting two vertices

Two faces can share a single edge

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Optimization Simplifies a smooth model with a

high number of faces Does not greatly change the

model’s appearance

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Building Organic Forms Humans are really hard to do Working with Meshes and Vertices Skinning

Working with cross-sections Can be provided by a scan

Magnetic Resonance (MR) 3D laser

Metaballs or Blobby surfaces

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Metaballs or Blobby surfaces Build a form from various sized

objects Blend the surfaces together into a

single mass

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Terrains Terrain objects can

be created from contour line data Editable splines are

selected a mesh surface

created over the contours

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Low polygon modelling What happens to a game if the

polycount in a model is too high? Too slow to play May crash the system

Overlapping meshes or undeleted faces may affect the appearance

Planning of low polygon models is important

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Spec-ing a low polygon model File format Number and type of polygons Use of texture maps

Particular type? Colour depth? Specific size? Transparency?

Examine any sample models

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Poly counts Total number of polygons that make up a

given object 3D engines have limits

Number they can move around in a given scene Software has a Polygon Counter utility

You can set a budget fop elected objects Unnecessary polygons can be removed

Use MultiRes Polygons can be made to look softer

Use MeshSmooth

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Level of Detail Models are created in two or more

levels of detail Use high polygon model when the

object is large in the scene Swap for the low polygon version

when zoomed out Used in VRML or X3D

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Billboard Define a flat surface which is

camera aligned Apply a texture Renders faster than if a 3D object is

used

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Box models and textures Simple way to add detail Keeps model simple Box with a texture added

More later with materials

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Low poly techniques No new skills Greater precision Decisions on where to invest detail Decisions on where to simplify

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Mesh structure Several meshes are attached to make

a single object Either

Weld the meshes together to form one mesh

Or separate them by a fractional amount

Do not intersect meshes Delete any hidden faces

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Game engines Real time 3D engines may use

rendering which smoothes out your model

You may need to take special steps to avoid this Detaching groups to make them sharp

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Self assessment What are the four types of modelling

concepts used by modelling software? What is the most useful for gaming?

Why is this used for gaming? Why does it not work well for

Rendered views? Organic shapes?

Discuss the four methods of converting 2D shapes to 3D Give an example of each for constructing

everyday objects

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References Adventure Gamers : Dreamfall: from sketch to

3D model http://www.adventuregamers.com/article/id,477/p,2, accessed 23/09/2005 Giambruno M, (2002) 3D Graphics & Animation, 2nd Edition, New Riders, ISBN: 0-7357-1243-3

Kerlow I. V., (2003) The Art of 3-D Computer Animation and Effects , 3rd Edition, John Wiley & Sons Inc; ISBN: 0471430366

Murdock K. L., 3ds max7 Bible, Wiley Publishing; ISBN: 0-7645-7971-1

Screen shots taken from 3ds max 7 User Reference and tutorials