let’s get technical… semantics of the course title: “solid” “modeling” (“procedural”...
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UCBUCB Let’s get technical…Let’s get technical…
Semantics of the Course Title:
“Solid” “Modeling” (“Procedural” …)
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UCBUCB What is a Solid ? What is a Solid ?
Examples of solids and non-solids:
What are the key properties of a solid?
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UCBUCB What is a Solid ? What is a Solid ?
Examples of solids and non-solids: YES: a block of steel, wood, styrofoam
NO: clouds, liquids,
?: a flexible wire, a rubber gasket, cloth ...
What are the key properties of a solid? Maintains shape in a predictable way
Has a well-defined surface
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UCBUCB Modeling -- as in “Describing”Modeling -- as in “Describing”
Why do we create models of solids ?
What do we want to do with these models ?
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UCBUCB Modeling -- What is the Purpose ?Modeling -- What is the Purpose ?
Why do we create models of solids ? For visualization, fabrication, analysis ...
What do we want to do with these models ? Analyze: mass, momenta, strength, flexibility, beauty,
reachability, assemblability, fluid flow in cavities, ...
What types of models are we interested in ? True solid shapes, with orientable 2-manifold surfaces,
mostly rigid, perhaps with predictable deformability;
and assemblies of such objects.
What is outside scope of CS 285 – Sp.2006 ? Collections of polygons that “look like” a forest,
water, clouds, fire, rainbow (--> rendering class)
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UCBUCB Modeling -- as in “Designing”Modeling -- as in “Designing”
Where do such models come from ?
Some reality capture process e.g., 3D scanning
Some procedural generation process maximizing/minimizing some functional
(e.g., minimize area as in soap bubbles)
Some creative design process realizing some desired functionality
capturing an aesthetic vision
( BUT NO RANDOM BLOBS ! )
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UCBUCB NoNo Random Blobs ! Random Blobs !
Many modeling systems are mostly suitable to make “lumpy potatoes” by moving dozens of control vertices individually.
We will concentrate on designed shapes:These are optimal in some local domain;any small change would make them inferior.
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UCBUCB NoNo Warped Quadrilaterals Warped Quadrilaterals
A single Bézier patch or rectangular B-spline array does not make a solid.
Again, there should be an element of “DESIGN.”Just randomly moving all control pointsis not in the spirit of CS 285.
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UCBUCB Make Computer (CAD) Models of:Make Computer (CAD) Models of:
Man-made Objects: utensils, furniture, machinery, buildings, sculptures, …
(these may have come from CAD models).
NOT: complete cities, complex vehicles, ...
Natural Objects: mountains, sea shells, tree trunks, bones, …
(these allow some procedural generation).
NOT: animals, forests, hedges, …
Visualization Models of: height functions, math surfaces, 4D objects, …
(these can be constructed procedurally).
NOT: fluid-flow vector fields ...
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UCBUCB How Do You Do How Do You Do ProceduralProcedural Design? Design?
Need an Appropriate Programming Language:
Auto-LISP in AutoCAD
Other CAD extensions
Mathematica
Matlab
C,C++
SLIDE (Unigrafix, OpenGL, Tcl) == >
For your course projects you can use whatever Programming/CAD environment makes you most productive.
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UCBUCB The PROs and CONs of SLIDEThe PROs and CONs of SLIDE
Lies between:
Mathematica / Matlab and
Traditional CAD tools (Solidworks, Autocad…)
Offers interactive fine tuning of critical parameters via some sliders, gives visual feedback.
Source code is under our own control.
Not a properly maintained system.
Tcl is a pain during the debugging process!
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UCBUCB Course Projects in CS 285Course Projects in CS 285
Design something that can be fabricated: Fancy casing for a wearable computer 3D visualization model of complex geometry Snap-together mechanism
A model to be explored by simulation: Strength / sound analysis on a mechanical part Manufacturability analysis on an injection mold
The chosen shape should offer some challengesthat can best be overcome by a small programming effort which will lead to a usable utility: Gear box --> gearwheel generator.
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UCBUCB Other Possible Course ProjectsOther Possible Course Projects
Parameterized Objects that can be fine-tuned and optimized:
Bells, Sculptures, Mechanisms, Containers,Puzzles, Mathematical Models, …
My own projects of current interest: Klein’s Quartic surface
Parameterized Bell
3D Penrose Tiles
More later in the course …
Approach me with your own ideas as soon as possible.
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UCBUCB HowHow to Make a CAD Model ? to Make a CAD Model ?
How would you make a CAD model of:
a plastic spoon,
a gear wheel,
an artistic part,
a math surface ?
Typically, this is a multi-stage process !
Study this process in Assignment #1
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UCBUCB Design of a CAD ModelDesign of a CAD Model
Multi-stage Design Process:
Initial Inspiration (Mental Image)
Clear Concept (Sketch, Mock-up)(refined by fabrication concerns)
Precise Part Description (CAD file)
Fabrication Plan (Machine readable)
Finished Part (Physical Artifact)
A1
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UCBUCB Get To Know Each Other !Get To Know Each Other !
Introductions…
Team Formations
Work Together !
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UCBUCB Extras ...Extras ...
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UCBUCB What is a Solid ? -- More AnswersWhat is a Solid ? -- More Answers
The Abstraction of a “Solid” Solids are composed of atoms
Atoms are mostly empty space
Smoothing and Sampling Use a finite-size probe to determine extent of a solid
The Boundary of a Solid How far the above probe can go
Level-set surface of a filtered density function
Why are these considerations relevant ? We often make approximations to an ideal shape,
e.g., use triangle mesh to represent a spline patch