3-Dimensional Modeling Docent: Marc van Kreveld BBL-484
[email protected] 1
3-dimensional modeling • Blok 4, bachelor informatica, niveau 3 – Gebonden keuzevak Gametechnologie – Discipline-gebonden keuzevak Informatica
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7.5 ECTS = 220 uur Gewijzigd t.o.v. vorig jaar (inhoud & docent) Colleges, geen werkcolleges, wel groot practikum Voorkennis: Graphics college
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3-dimensional modeling • Specifieke voorkennis: – – – – –
vectoren, matrices, transformaties functies, polynomen, logaritmen, trigoniometrie statistiek: stadaarddeviatie, regressie, … algoritmiek: aanpak, efficiëntie programmeren: C# / C++
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3-dimensional modeling, practicum • Begeleid practikum, altijd na college, in drie groepen, tegelijk (2 x 2 uur/week) • 3 opdrachten – Modelleren met Blender: hand en monster – Splines implementeren: Bezier en B-spline – RANSAC experimenteel onderzoek om vlakken te vinden
• Stel het werk niet uit tot de inleverdag! Die dag is het vaak extra druk in de practikumzalen en is de begeleiding ook drukker 4
3-dimensional modeling, practicum • Twee begeleiders – Frank Staals (groepen 1 en 2) – Benny van der Vijgh (groep 3)
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3-dimensional modeling, cijfers • • • • • •
Kleine tussentoets: 15% Eindtentamen: 40% Practische opdrachten: 15% elk (3x) Geen onderdeel met cijfer 4 of lager toegestaan Eindtentamen minstens een 5 Gewogen gemiddelde afgerond een 6 of hoger (dus onafgerond minstens een 5.5) geslaagd
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3-dimensional modeling, informatie • Informatie op de website • Feedback/vragen per e-mail naar de docent • Feedback/vragen over het practikum naar je practikumbegeleider Frank of Benny (niet naar mij!) • Jouw tijd: – college: 14x2 uur, voor-/nastudie: 14x4 uur = 84 uur – practikum: begeleid 14x2 uur, zelf uitzoeken (installeren, leren, uitwerken) 14x4 uur = 84 uur – tentamen+voorbereiding: 20(?) uur
Totaal: ongeveer 200 uur 7
3-dimensional modeling, materiaal • Verschillende bronnen (er is geen geschikt boek voor alle onderwerpen) – – – –
Curves Graphics boek van Shirley & Marschner Mesh representation deels zelfde boek Rest papers, surveys, wikipedia info Alles: slides zelf
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3-dimensional modeling, colleges • Er is geen werkcollege, maar tijdens het college worden wel opgaven gemaakt (vaak de 10-15 minuten vóór de pauze of het eind) – sommetjes – begripvragen – discussievragen
• Werk met je buurman/vrouw, zeker voor de discussievragen
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3-dimensional modeling, schema • Let op het rooster dat on-line staat • Eerste weken: – 23 april: Introductie, nu – 25 april: Geen college; Indievelopment conference – 30 april: Geen college; Koninginnedag – 2 mei: Curves I – 7 mei: Curves II – 9 mei: Geen college; Hemelvaartsdag 10
3-dimensional modeling, lecturer • is geen expert 3-dimensionaal modelleren • is geen expert implementeren, C#, Blender, … • is wel expert in algoritmen, meetkundige algoritmen
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3-dimensional modeling motivation and overview
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3-dimensional modeling • Related to graphics, but not concerned with rendering, shading, textures, GPU, … • Instead, concerned with geometry, shape • As a research field, part of graphics and as an independent research field – SIGGRAPH conference – Symposium on Geometry Processing – Shape Modeling International
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Some pictures
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More pictures
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Icons of 3D modeling
Stanford bunny
Utah teapot
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Some Utah teapot images
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Global 3D modeling pipeline
data acquisition
clean-up
hand-drawn modeling
build model
consistency check procedural modeling
consistency check
use/render/ align with another model 18
Data acquisition methods • 3D scanning – consumer 3D scanners – coordinate measurement machines (CMM) – LiDAR scanning (airborne, ground-based) – CT scan, MRI scan
• Stereo photography (SIFT points)
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3D modeling software • • • • • •
Blender (free, open source) Autodesk Maya Autodesk 3DS Max (was: 3D Studio Max) Cinema 4D Google sketch-up … for hand-generated models, often also procedural generation, rendering, animation, video generation, … 20
Procedural modeling • L-grammars • Fractals
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Main types of 3D models • Unstructured “models” – 3D point clouds
• Boundary models – polygon meshes – curves and surfaces – implicit models
• Solid models – constructive solid geometry (CSG) – voxel models 22
Quality in 3D modeling • Geometric quality: close to the desired model (in some distance measure) • Continuity, smoothness • Topological quality: the right holes and loops • Consistency: if triangle A stores triangle B as an adjacent triangle, then triangle B should store A as an adjacent triangle too 23
Efficiency in 3D modeling • 3D point clouds are large – to find the 10 nearest neighbors of each point, we do not want to scan the point set many times spatial search structures
• 3D models consist of many elements (triangles) – to find the elements adjacent to a given element, we do not want to scan the whole model adjacency representation of model
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Stanford bunny (1994)
Maximum resolution of mesh: 69,451 triangles from 3D scanning
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Happy buddha (1996, Stanford)
Maximum resolution of mesh: 1,087,716 triangles from 3D scanning 26
Actueel Hoogtebestand Nederland
Airborne LiDAR scanning: ~ 135 x 109 height points (every 0.5x0.5 m), precision 5 cm (version AHN-2, 2012) 27
Reasons for 3D modeling • • • • • • • •
CAD/CAM, rapid prototyping, industrial design Movie industry Gaming industry (entertainment and serious) Scientific (geology, hydrology, physics simulation) Medical, surgery Architecture, urban planning Robotics Monitoring 28
Reasons: CAM/CAM • Milling cutter • Use of molds • Stereo lithography
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Reasons: movie industry • Futureworld (1976): first use of 3D wireframe animation • Pixar 1986 (1979) • Toy story (1995): first full-length, computer animated movie
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Reasons: gaming • Entertainment • Serious, for training
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Reasons: scientific • Geology, erosion • Water and air flow
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Reasons: medical, surgery • Reconstruction from CT or MRI scans • Deformable tissue modeling • Dental models
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Reasons: architecture
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Reasons: robotics
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Reasons: monitoring • Forest: growth/health • Coast, beach: sand loss
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Main topics of the lectures • • • • • • •
Curves, splines Boundary representations Implicit models Triangular meshes and reconstruction Urban reconstruction from point clouds Efficiency and data structures Procedural modeling
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Other courses related to 3DM • • • • • • •
Interaction technology (level 3) Image processing (level 3) Motion and manipulation (master GMT) Multimedia modeling (master GMT) Geometric algorithms (master GMT) Multimodal interaction (master GMT) Computer animation (master GMT)
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Academic honesty Academic honesty is compulsory in accomplishing the assignment, projects, and the exams. Exchanging code with others is not allowed. Using code from the previous year or from the internet is prohibited, unless stated otherwise in the lectures. Copying texts of the reports from other groups is strictly prohibited. Generally, cheating, academic misconduct, plagiarism, and fabrication of output by other means than by your own implementation are not tolerated. We will use software to detect any code or text plagiarism. Any violation to the academic honesty will imply a fail to pass the course. 39
