“Perspective Based Level of Detail Management of Topographic Data”
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“ “ Perspective Based Perspective Based Level of Detail Management Level of Detail Management of Topographic Data” of Topographic Data” By: By: Morten Granlund Morten Granlund Supervisor: Gunnar Misund Supervisor: Gunnar Misund http://www.ia-stud.hiof.no/~mortengr
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“Perspective Based Level of Detail Management of Topographic Data”. By: Morten Granlund Supervisor: Gunnar Misund. http://www.ia-stud.hiof.no/~mortengr. Level of Detail. “Easing the burden of the 3D renderer…”. The basics of Level of Detail. GOAL: Render 3D graphics fast! - PowerPoint PPT Presentation
Transcript of “Perspective Based Level of Detail Management of Topographic Data”
““Perspective BasedPerspective BasedLevel of Detail ManagementLevel of Detail Management
of Topographic Data”of Topographic Data”
By: By: Morten GranlundMorten Granlund
Supervisor: Gunnar MisundSupervisor: Gunnar Misund
http://www.ia-stud.hiof.no/~mortengr
Level of DetailLevel of Detail
““Easing the burden of the 3D Easing the burden of the 3D renderer…”renderer…”
The basics of The basics of Level of DetailLevel of Detail
GOAL: Render 3D graphics fast!GOAL: Render 3D graphics fast! SOLUTION: Several levels of detail.SOLUTION: Several levels of detail.
More on LoDMore on LoD
One square has a fixed data-sizeOne square has a fixed data-size A model is more accurate if:A model is more accurate if:
a)a) The model has more squares.The model has more squares.
b)b) Each square covers a smaller area.Each square covers a smaller area.
Tree StructureTree Structure
Level 0 Square covers >200 km
Level 1 Square covers 100-200 km
Level 2 Square covers 50-99 km
zoom
zoom
Rez…Rez… ……is an Open Source framework for is an Open Source framework for
translating terrain data.translating terrain data. ……creates Level of Detail hierarchies.creates Level of Detail hierarchies. ……creates two parallel hierarchies:creates two parallel hierarchies:
• TilesTiles• TreesTrees model
tiles
trees
TilesTiles
Tree containing VRML Tree containing VRML datadata..• Each node is called a Each node is called a tile.tile.• Each tile contains a matrix with heights Each tile contains a matrix with heights
(elevation grid).(elevation grid).
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tiles
TreesTrees The Trees hierarchy contains the The Trees hierarchy contains the structurestructure.. The trees structure consists of a file hierarchy The trees structure consists of a file hierarchy
parallel to the tiles.parallel to the tiles. A trees node is a “wrapping” around each tile.A trees node is a “wrapping” around each tile.
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A “Trees”-node has:A “Trees”-node has:
• Reference to Parent nodeReference to Parent node• Reference to Children nodes (x4)Reference to Children nodes (x4)• Reference to the terrain data (Reference to the terrain data (tiletile node) node)
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