Post on 17-Jan-2018
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Business and Computing Deanery
3D Modelling Tools
Week 4 Low polygon modelling
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From previous week The importance of lining things up
Snaps, grid, align Cloning Arrays Grouping Modifiers
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This week Low polygon modelling Working with sub-objects
Collect portfolio 1
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Editable objects Do not have the same flexibility of
parameters They deal with sub-objects and
editing functions Editable objects include:
Meshes Polygons Patch Splines Murdock K.L., (2005)
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Editable objects Are not created They are converted from another
object, usually a primitive Loose their parametric properties
after they have been converted Edit sub-objects
Edges Vertices Faces
Murdock K.L. (2005)
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Surface Modeling Surface modeling is more free form
than geometric (parametric) modeling
Use the modifier stack to “collapse” a parametric model to some form of editable surface
Once you have done so, a variety of tools let you shape the surface
3ds max v7
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Modeller concepts Types of modelling systems:
Parametric Mesh Polygon Spline Patch
Many 3D modelling tools combine two or more of these basic techniques Giambruno M, (2002)
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Parametric modellers Retain their base geometric
information Default shape Current size Segments
This information can be accessed and altered
Can be spline or polygon based
Deformations can be applied
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Polygon modellers Objects constructed
with polygons Made up of tiny, flat
surfaces More polygons
mean More detail Bigger file sizes
Low polygon Used in real-time
games Small file sizes Quick to render
3ds max v7
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Polygons Objects composed of faces An editable poly is a polygonal mesh
Unlike an editable mesh, it uses more than three-sided polygons
Five sub-object levels Vertex Edge Border Polygon Element
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Meshes A mesh object made up of triangular
faces as an object and at three sub-object levels Vertex Edge Face
Faces are smoothed together when rendered
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Spline modellers A line defined as points, usually
curved Resolution independent
No faces Useful for creating organic shapes Different types
B-spline Bezier NURBS
Non-uniform rational b-splinesGiambruno M, (2002)
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Spline types B-spline Bezier NURBS
More information at http://www.doc.ic.ac.uk/~dfg/AndysSplineTutorial
3D Graphics and animation
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Patch modellers Use a network of control
points Lattice of splines or
polygons Stretch or tug on the
shape Useful for organic forms
3ds max v7
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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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Why do I want to count them?
Which to use? Check with your game engine
Some still require that all faces be coplanar
Working with polygon is quicker More advanced editing features with
Max Polygon count feature
Sometimes the terms are interchanged!!!
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Converting to editable objects Use the Quad
menu Or
Right click the object in the Modifier Stack
3ds max v7
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Converting to editable objects 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
You can convert between different types but each conversion may subdivide the object
You can apply a modifier to convert an object Retains the parametric qualities of the object, but
you cannot edit the mesh
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Editable Mesh Surface Polygon mesh
3ds max v7
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Working with sub-objects Insert a vertex Multiple selection
Control + click Draw a lasso Select region
3ds max v7
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Edit face A face is the smallest possible mesh
object A polygon formed by three vertices
Faces provide the renderable surface of an object
3ds max v7
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Extrude Extrude Bevel
3ds max v7
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Cut Sub-divide a mesh Create another edge Useful to use snap To start from a different
point, right-click To finish cutting, right-click
twice
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Bridge Bridging two elements makes them
contiguous, combining them into a single element
3ds max v7
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Activity Make a crown
Create a tube Convert to an editable poly Extrude polygons
Try bridging some 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"
3ds max v7
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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
3ds max v7
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Activity Make a face
Create a sphere Convert to a polygon Push and pull vertices to make a face
using soft selection 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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Poly counts Total number of polygons that make
up a given object 3D rendering engines have limits Software has a Polygon Counter
utility You can set a budget for selected
objects
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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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Portfolio 2 Repeat a much as possible of Portfolio 1 using
low polygon modelling techniques Count the polygons, record the number on your
paper submission
Screen grab of 3ds max of your model of: A room created from primitives
Floor 3 walls
Containing a table Rectangular table top Four rectangular legs
Plus three chairs or stools
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Next week Lecture
2D to 3D modelling Storyboards
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Impendent study Directed reading 3DS Max 7 Bible
Read Chapter 13 Portfolio 2 Presentation Tutorials
Chess Set
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Questions You have been asked to model an
aeroplane for use in a game What do you need to know before you
start modelling Describe the difference between
geometric and surface modelling, which method would you use, justify your choice
Describe the difference between mesh and polygon modelling, which method would you use, justify your choice
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References 3ds max v7, (2005) User Reference and
Tutorials 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., (2005) 3DS Max 7 Bible, John Wiley & Sons Inc, ISBN: 0764579711