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Business and Computing Deanery
3D Modelling Week 3
Advanced modelling
3D Modelling 2
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
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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