Video Review :) Monday 2 February:

• Interactive Boundary Computetion of Boolean Combinations of Sculptured Solids
  Studies the model of a Bradley vehicle on an SGI, the problem of avoiding colisions.
  Interactive design, real time very important ( used in CAD applications).
  3D problem. Key words: boolean operations, boundary representations.
• OBB-Tree
  Deals with the possibility of obtaining smooth models. There were different
  models shown, for example the engine-piston one. All are on SGI.
  Key words: rejection set, colision query ( lots of rectangles there!:)
  3D problem, performance and complexity very important as the alghorithm was
  supposed to run in real time.
• walkthrough 96, Real Time Rendering of Massive Models Definition of massive models (> 500 pieces), the problem is the time consumed
  to render them. Solution: rendering only the noticeable parts ( in view) and
  constructing smaller models.
  3D problem.
  Key words: the problem of Portals and Mirors, Dynamic Texture-Based Simplification,
  Radiosity, Envelope Surfaces (simplifies the algorithm about 2-3 times, preserving
  the quality), triangles.
• The 5th Annual Video Review of Computational Geometry The (approximative) titles would be:
  • Radiosity in Flat Land Made Visibly Simple
  • Enumerating: Delaunay Flip
  • Reverse Search
  • Enumeration of Regular Triangles
  • Four Polytops and a Funeral (for me)
  • A Package: Triangulations
  • Impulse-Based Simulation
  ...and what they were about:
  • Radiosity, reflection, used for constant illumination, rendering immages.
    Key-words: duality transform, visibility complex, the form factor, meshing, umbra,
    penumbra. 3D problem.
  • Testing central systems through direct simulations of impulses.
    Colision symulation, 3D problem. Key -words: Culling checks, spatial partition, multibodyes, convex hulls, rotation
    diagram, placement poligon, power of coherence, parametric surfaces.
    View problem, colision detection. Uses Delaunay triangulations.
  • Polytops, a 3D versus 2D problem, define and deform a polytop.
    Contains minimum weight edges problem -> minimum weight triangulations.
    Problems with the complexity of the algorithm.
  • Triangulations, min weight (total length of edges), Markov chain and random
    generation. Uses the adjacency graph.

Wednesday 4 February:
Two tapes:

• The 4th Annual Video Review of Computational Geometry
  • Hip Air
    3D problem, studies the motion in mechanism.
    Key -words: contact ( constrains moving), configuration space, toleracing.
    Problems: jamming, multiple mechanisms, Fuji camera.
  • 3D Modelling-Delaunay Triangulations
    Studies the reconstruction of a bone-shape from magnetic images of its sections.
    Key-words: contour, Voronoy diagrams, triangulation. 2D versus 3D ( through projections).
  • Incremental Collision Detection for Polygonal Models
    Polytops, convex-non convex objects.
    Colision problem, tori simulated motion.
    Key-words: Depth First Search, Voronoy diagram.
  • Convex Surface Decomposition
    The problem of boundary selection and decomposing of boundaries of real-life
    objects. 3D problem. Key-words: convex hall, Breath First Search, minimal surface decomposition.
  • Visibility Complex, not enough time:), lots of projection in 2D.
  • Animation of Euclid Proposition
• The 6th Annual Video Review of Computational Geometry
  • The Bisector Surface of Freeform
    Bisector plans.
    Key-words: rational space curves, planar versus 3D curves, B&ecute;zier curves.
    Nice images.

3D Visibility Made Visibly Simple ( again:)
An introduction to the Visibility Skeleton, umbra, penumbra, graphs associated
the visibility problem.
The room model. Key-words: light source, visibility, umbra, penumbra.

Application of an Effective Geometric Clustering Method to Color Quantization Problem
Key-words:Clustering problem, minimazing the cost, K-clustering.
Aplication in photo-modifications, quality.

Animating the Offset Poligon.
Distance function, robot localization, local offset objects.
Key-words: Voronoy diagram, scaled polygons versus offset polygons ( they
shrink till they become a point).
Useful for finding the Voronoy diagram.

Triangulation-Based Object Reconstruction Methods.
Approx 3 steps:

• Point sampling, 3D Delaunay, A-alpha-shapes->
• dense triangle mesh, mesh simplification, base mesh->
• A-patch fitting, C one smooth mashed.
  It has several advantages, but disadvantages too.
• Approximating Weighted Shortest Paths on Polyhedral Surfaces
  Key-words: Polyhedral terrain, weight-cost, shortest cross path.
  Problem: finding paths on weighted terrains, algorithmic complexity.
  Several approaches, first associate a graph to the terrain ( bad approx).
  Improvement -> add steiner points to the graph, fine tuning ( unweighted),
  with linear time, fine tuning ( weighted), more precise, but more complex too.

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