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Michela Mortara, Chiara Catalano, Bianca Falcidieno Shape Modelling Group CNR-IMATI Genova. Computer Graphics recipes for analyzing and enhancing shape information . Endowing 3D shapes with Semantics in Virtual Worlds. Overview. Basics on 3D digital shapes : - PowerPoint PPT Presentation
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Computer Graphics recipes for analyzing and enhancing shape
information Endowing 3D shapes with Semantics in Virtual Worlds
Michela Mortara,Chiara Catalano,Bianca FalcidienoShape Modelling GroupCNR-IMATI Genova
Overview Basics on 3D digital shapes:
Creation of a 3D model Representation of 3D models
Not only geometry and graphics but knowledge carriers in many domains
Endowing 3D models with semantics in Virtual Worlds: why and how Analysis of 3D models Annotation of 3D models and their components
Digital 3D Shapes 3D Models
Single models Assemblies Environments
What are 3D models useful for? gradual shift of paradigm in science from
physical prototypes and experience to virtual prototypes and simulation
CAD/PLM Bioinformatics Medicine Cultural Heritage …
3D models in games: complex and convincing virtual worlds realistic environment and characters realistic interactions and behaviour
Trough a laser scanner a digital copy of the real object is made
Using a modeler, the designer creates a digital objects from
his/her idea
Creation of a 3D model
or
Cortesia Alessi
Acquisition
Digital Shape
Acquisition & Reconstruction
Real object
Laser Scanner
Processing of the raw data to build up an accurate 3D model (meshing)
There are several steps to obtain the final model Several scans of the object
must be acquired…
The details of the process
There are several steps to obtain the final model Several scans of the object
must be acquired… Then the scans must be
aligned…
The details of the process
There are several steps to obtain the final model Several scans of the object
must be acquired… Then the scans must be
aligned…
The details of the process
There are several steps to obtain the final model Several scans of the object
must be acquired… Then the scans must be
aligned… And finally all the scans are
merged into a single model
The details of the process
There are several steps to obtain the final model Several scans of the object
must be acquired… Then the scans must be
aligned… And finally all the scans are
merged into a single model
The details of the process
Finally the post-processing: Geometric checks and repairing
intersections, degeneracies, singularities, etc.)
Hole filling Smoothing Simplification Textures ...
The details of the process
Examples
simplification resampling
remeshing
texturing
Mathematical Model Representation
z = f(x,y)
…
Physical Object Digital Model
Paradigm of Geometric Modelling
Computer restrictions
Restrictive hypothesis
Representation Schemes Boundary Schemes (e.g. meshes) Volumetric Schemes
Decomposition Schemes Object-based (e.g. tetrahedrization) Spacial enumeration (e.g. voxelization)
Constructive Schemes Based on half-spaces Based on Primitives (CSG)
3D and Technology today Technological advances highly reduced the
costs of 3D content acquisition, storage and transmission
But how to… organize, process, share, use
and re-use, navigate, this largeamount of complex content ?Are there similar objects in the
repository? What is its functionality?
#VRML V1.0 asciiSeparator { Coordinate3 { point [ -1.595000 -1.101000 4.897000, -1.537000 -0.933000 4.899000, -1.681000 -0.995000 4.885000, -1.712000 -0.948000 4.876000, -1.589000 -0.765000 4.893000,
…
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