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Explore Progressive Simplicial Complexes (PSC) for efficient 3D model representation with continuous LOD sequences and smooth visual transitions. Understand how PSC supports topological changes and arbitrary dimension models, presented through a comparison with Progressive Meshes. Discover the space-efficient and progressive transmission features of PSC for complex 3D digital rendering applications.
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Progressive Simplicial Complexes Jovan Popovic Carnegie Mellon University Hugues Hoppe Microsoft Research
Complex Models • Rendering • Storage • Transmission 232, 974 faces
150 152 500 13,546 ^ Mn=M M1 M175 M0 M0 vspl0 … vspli … vspln-1 … vspli … vspl0 vspln-1 Progressive Mesh (PM) representation Previous Work • Progressive Meshes [Hoppe, ‘96]
PM Features • Continuous LOD sequence • Smooth visual transitions (Geomorphs) • Progressive transmission • Space-efficient representation
Would also like: PM Restrictions • Supports only “meshes” (orientable, 2-dimensional manifolds)
M0 Mn PM Restrictions • Supports only “meshes” (orientable, 2-dimensional manifolds) • Preserves topological type
2,522 8,000 167,744 PM Restrictions • Supports only “meshes” (orientable, 2-dimensional manifolds) • Preserves topological type M0 Mn … Mi …
PM edge collapse(ecol) vertex split(vspl) Progressive Simplicial Complexes (PSC)
Previous Work • Vertex unification schemes [Rossignac-Borrel ‘93] [Schaufler-Stürzlinger ‘95]
PM PSC edge collapse(ecol) vertex unification(vunify) vertex split(vspl) Progressive Simplicial Complexes (PSC)
PM edge collapse(ecol) vertex split(vspl) Progressive Simplicial Complexes (PSC) PSC vertex unification(vunify) generalized vertex split(gvspl)
^ M V K Simplicial Complex
^ M Simplicial Complex V K
^ M 6 4 2 3 1 7 5 abstract simplicial complex = {1, 2, 3, 4, 5, 6, 7} + simplices {1}, {2}, … 0-dim Simplicial Complex V K
^ M V K 6 4 2 3 1 7 5 Simplicial Complex abstract simplicial complex = {1, 2, 3, 4, 5, 6, 7} + simplices {1}, {2}, … 0-dim {1, 2}, {2, 3}… 1-dim
^ M V K 6 4 2 3 1 7 5 Simplicial Complex abstract simplicial complex = {1, 2, 3, 4, 5, 6, 7} + simplices {1}, {2}, … 0-dim {1, 2}, {2, 3}… 1-dim {4, 5, 6}, {6, 7, 5} 2-dim
arbitrary simplicial complexes ^ Mn=M PSC Representation M1 M22 M116 gvspl1 … gvspli … gvspln-1 PSC representation
PSC Features Video • Destroyer PSC sequence • PM, PSC comparison • PSC Geomorphs • Line Drawing
vunify Generalized Vertex Split Encoding
ai gvspli = {ai}, Generalized Vertex Split Encoding vunify gvspl
Connectivity Encoding case (1) case (2) case (3) case (4) 0-dim undefined undefined 1-dim 2-dim
Connectivity Encoding case (1) case (2) case (3) case (4) 0-dim undefined undefined 1-dim 2-dim
Connectivity Encoding case (1) case (2) case (3) case (4) 0-dim undefined undefined 1-dim 2-dim S
4 0-simplices Generalized Vertex Split Encoding vunify ai gvspl gvspli = {ai},
Generalized Vertex Split Encoding vunify ai gvspl gvspli = {ai}, 4 34122 1-simplices
Generalized Vertex Split Encoding vunify ai gvspl gvspli = {ai}, 4 34122 12 2-simplices
Generalized Vertex Split Encoding vunify ai gvspl gvspli = {ai}, 4 34122 12 connectivity S
vpos Generalized Vertex Split Encoding vunify gvspl gvspli = {ai}, 4 34122 12,
1 1 1 1 1 1 1 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4 Connectivity Encoding Analysis vunify gvspl example: 15 bits models (avg): 30 bits
Connectivity Encoding Constraints vunify gvspl 1 1 1 1 1 1 1 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4
example: 15 bits models (avg): 30 bits example: 10.2 bits models (avg): 14 bits Connectivity Encoding Compression vunify gvspl 1 1 1 1 1 1 1 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 4
Space Analysis • Average 2D manifold mesh n vertices, 3n edges, 2n triangles • PM representation n ( log2n + 4 ) bits • PSC representation n ( log2n + 7 ) bits
Form a set of candidate vertex pairs 1-simplices of K 1-simplices of KDT candidate vertex pairs PSC Construction
PSC Construction • Form a set of candidate vertex pairs • 1-simplices of K 1-simplices of KDT • Compute cost of each vertex pair • ∆E = ∆Edist + ∆Edisc + E∆area + Efold • Unify pair with lowest cost • updating costs of affected candidates
Simplification Results 72,346 triangles 674 triangles
Simplification Results 8,936 triangles 170 triangles
^ M PSC Summary PSC V K lossless M1 gvspl arbitrary simplicial complex single vertex • progressive geometry and topology • any triangulation
PSC Summary • Continuous LOD sequence • Smooth transitions (Geomorphs) • Progressive transmission • Space-efficient representation • Supports topological changes • Models of arbitrary dimension e.g. LOD in volume rendering