ahmedabad-visual design office kolhapur-mechanical design office saki naka – die manufacturer...
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• Ahmedabad-Visual Design Office
• Kolhapur-Mechanical Design Office
• Saki Naka – Die Manufacturer
• Lucknow- Soap manufacturer
A Solid Modeling Fable
Ahmedabad-Visual Design
• Input: A dream soap tablet
• Output:• Sketches/Drawings• Weights• Packaging needs
Soaps
More Soaps
Ahmedabad (Contd.)
Top View
Front View Side View
Kolhapur-ME Design Office
• Called an expert CARPENTER
• Produce a model (check volume etc.)
• Sample the model
and produce a data-
set
Kolhapur(contd.)
Kolhapur (contd.)
• Connect these sample-points into a faceting
• Do mechanical analysis
• Send to Saki Naka
Saki Naka-Die Manufacturer
• Take the input faceted solid.
• Produce Tool Paths • Produce Die
Lucknow-Soaps
• Use the die to manufacture soaps
• Package and transport to points of sale
Problems began…
• The die degraded in Lucknow
• The Carpenter died in Kolhapur
• Saki Naka upgraded its CNC machine
• The wooden model eroded
But
The Drawings were there!
So Then….
• The same process was repeated but…
The shape was different!
The customer was suspicious and sales dropped!!!
The Soap Alive !
What was lacking was…A Reproducible Solid-
Model.• Surfaces defn• Tactile/point
sampling• Volume
computation• Analysis
The Solid-Modeller
Modeller
OperationsRepresentations
The mechanical solid-modeller
Operations• Volume
Unions/Intersections• Extrude holes/bosses• Ribs, fillets, blends
etc.
Representation• Faceted Solid• Cloud of Points• STEPP• Boundary-Rep (b-rep)• .sldprt
Examples of Solid Models
Torus Lock
Even more examples
Slanted Torus Bearing
Examples (Contd.)
Solid Model of an Ice-Cream Machine
Sample Representations
Other Modellers-Surface Modelling
Chemical Plants
• Design Rules
-process rules
-tolerances• Civil-Mechanical
Co-Design
-facility design
-accessibility
-safety
Chemical plants (contd.)
Chemical Plants (contd.)
Advanced Surface Modelling
Human Cortex
Manual Surface Sampling,/ model consists of 24,000 planer facets
Advanced Surface Modelling (Contd.)
The above surface model was created by using the
software tool (Nuages) by Bernard Geiger
Voxel based re-construction shows the surface decimated to about 22500 vertices and 45000 triangles
Our Course-Theory
• Topology-combinatorial entities and their relationships
• Geometry- parametrizable entities and their representations
• Operations- some of them and their implementations
source:www.cse.iitb.ac.in/~sohoni CAGD course notes
Our Course-Applications
• Basic solid-modelling
• Design Trees and re-parametrization
• MIL (B-rep) and geometry
Course Schedule
Time AM AM PM PM
Day 1 SM-Fable.ppt SM-Primer.ppt
SM-Practical
Tutorial
3d
Day 2 SMInternals.ppt
Geometric-Topology
Polynomials.pdf
Tutorialpolynomials
Day 3 Curves.pdf Surface.pdf Application I
TutorialCurves and Surfaces
Day 4 Spline.pdf Operation.pdf
Application II
TutorialOpns/Cons.
Day 5 Construction.pdf
Wrap-Up ApplicationIII
TEST
Contents I
SM-Fable Motivate SM, examples SM and structure of SM
SM-Primer Practical introduction to an SM
SM-Internals Kernel/Husk dichotomy. Entities-face/edge/co-edge.
Topology and applications
Geometry-Topology
The two-tier representation. Parametric vs. Implicit. Sample parametrizations, trim curves
Polynomials Polynomials and the approximation problem, lagrange interpolation, and the bernstein base
Curves The construction of Bezier-Bernstein curves, control polygons, end calculations, elevation
Surfaces The 2d analogue of bernstein. Tensor-product surfaces, end conditions
Contents II
Splines The piece-wise polynomial paradigm, knot insertion and evaluation
Operations TheNewton/Raphson Solver, the projection problem, intersections
Constructions The constructor, intersection curves, extrudes, blends