Efficient Rendering of Heterogeneous Polydisperse Granular Materials - PowerPoint PPT Presentation

Efficient Rendering of Heterogeneous Polydisperse Granular Materials Thomas Müller 1,2 Marios Papas 1 Markus Gross 1,2 Wojciech Jarosz 3 Jan Novák 1 1 Disney Research 3 Dartmouth College 2 ETH Zürich

Efficient Rendering of Heterogeneous Polydisperse Granular Materials 2

Efficient Rendering of Heterogeneous Polydisperse Granular Materials Larry Hoffman – CC BY 2.0 3

Efficient Rendering of Heterogeneous Polydisperse Granular Materials Krissie Camealy – CC BY 2.0 4

Efficient Rendering of Heterogeneous Polydisperse Granular Materials *Micky – CC BY-SA 2.0 5

Efficient Rendering of Heterogeneous Polydisperse Granular Materials Marco Verch – CC BY 2.0 6

Efficient Rendering of Heterogeneous Polydisperse Granular Materials yeowatzup – CC BY 2.0 7

THE APPEARANCE OF GRANULAR MATERIALS byrev – CC0 *Micky – CC BY-SA 2.0 yeowatzup – CC BY 2.0 Larry Hoffman – CC BY 2.0 Krissie Camealy – CC BY 2.0 8

DECOMPOSITION OF GRANULAR APPEARANCE [Meng et al. 2015] 11

LOW ORDER AND HIGH ORDER Low order = + Full image High 12 order

LOW ORDER AND HIGH ORDER — INDIVIDUAL PHOTONS 13

LOW ORDER AND HIGH ORDER — PATH TRACING 14

ACCELERATING HIGH ORDER WITH SHELL TRACING Explicit Path Tracing Shell Tracing [Moon et al. 2007] 15

METHODS OVERVIEW High order Low order Moon et al. 2007: Explicit Path Tracing Shell Tracing - Per-grain material precomputation - Only homogeneous Meng et al. 2015: Ours: 16

ACCELERATING HIGH ORDER WITH CONTINUOUS APPROXIMATION Meng et al. 2015: Grains Continuous volume 17

METHODS OVERVIEW Low order High order Moon et al. 2007: Explicit Path Tracing Shell Tracing - Per-grain material precomputation - Only homogeneous Meng et al. 2015: Volumetric PT + Diffusion Explicit Path Tracing - Per-grain type precomputation - Only homogeneous & monodisperse Ours: (Explicit PT + ) Proxy PT Volumetric Shell Tracing - Per-grain type precomputation - One-time global precomputation 18

Proxy Path Tracing For accelerating low order light transport

PROXY REPRESENTATION OF GRAINS 𝜕 𝑗 𝐲 𝑗 𝜕 𝑗 𝐲 𝑗 𝐲 𝑝 𝐲 𝑝 𝜕 𝑝 𝜕 𝑝 Grain Spherical proxy 20

DIMENSIONALITY REDUCTION OF PROXY REPRESENTATION 8D 21

DIMENSIONALITY REDUCTION OF PROXY REPRESENTATION 8D 5D 3D 24

PROXY PATH TRACING RESULTS — SMALL SCALE Explicit PT (reference): 369 hours Proxy Path Tracing (ours): 34.3 hours (10.7x) 25

PROXY PATH TRACING RESULTS — SMALL SCALE Explicit PT (reference): 369 hours Proxy Path Tracing (ours): 34.3 hours (10.7x) Explicit + Proxy PT (ours): 73.7 hours (5x) 26

PROXY PATH TRACING RESULTS — LARGE SCALE Explicit PT Meng et al. 2015 Proxy PT (ours) (reference) 19.4 hours 722 hours 1588 hours (82x) (2.2x) 27

PROXY PATH TRACING RESULTS — LARGE SCALE Explicit PT (reference) 1588 Explicit PT (reference) 1588 hours hours Meng et al. 2015 722 Proxy PT (ours) 19.4 hours hours 28

PROXY PATH TRACING RESULTS — LARGE SCALE Explicit PT (reference) 1588 Explicit PT (reference) 1588 hours hours Meng et al. 2015 722 Proxy PT (ours) 19.4 hours hours 29

METHODS OVERVIEW High order Low order Moon et al. 2007: Explicit Path Tracing Shell Tracing - Per-grain material precomputation - Only homogeneous Meng et al. 2015: Volumetric PT + Diffusion Explicit Path Tracing - Per-grain type precomputation - Only homogeneous & monodisperse Ours: ✓ Volumetric Shell Tracing (Explicit PT + ) Proxy PT - One-time global precomputation - Per-grain type precomputation 30

Volumetric Shell Tracing For accelerating high order light transport

SHELL TRANSPORT FUNCTION 𝐲 𝑝 𝐲 𝑝 𝜕 𝑝 𝜕 𝑝 𝐲 𝑗 𝐲 𝑗 𝜕 𝑗 𝜕 𝑗 Spherefilled Shell with medium Transport Function 32

SHELL TRANSPORT FUNCTION — MOON ET AL. 2007 𝐲 𝑝 𝜕 𝑝 Moon et al. 2007: 𝐲 𝑗 𝜕 𝑗 Grains Spherefilled with grains 33

SHELL TRANSPORT FUNCTION — OURS 𝐲 𝑝 𝜕 𝑝 Ours: 𝐲 𝑗 𝜕 𝑗 Continuous approximation [Meng et al. Spherefilled 2015] with continuous approximatio n 34

SHELL TRANSPORT FUNCTION — OURS Why continuous volumes? - Significantly faster pre-computation ( ~1000x ) - Enables dense dictionary of shells! RTE parameter space (HG phase function) High-resolution dictionary of shells over full RTE space (240 MB, 10h precomputation on workstation) 35

SHELL TRACING IN HETEROGENEOUS VOLUMES (CONSERVATIVE) Dictionary of Shells Binary heterogeneous volume 36

SHELL TRACING IN HETEROGENEOUS VOLUMES (GREEDY) Dictionary of Shells Binary heterogeneous volume 37

SHELL TRACING: GREEDY VS. CONVERVATIVE (THICK MEDIUM) Volumetric PT (reference): 802 hours Cons. Shell Tracing (ours): 173 hours (4.6x) Greedy Shell Tracing (ours): 155 hours (5.2x) 38

SHELL TRACING: GREEDY VS. CONVERVATIVE (THICK MEDIUM) Volumetric PT (reference): 802 hours Relative Squared Error Cons. Shell Tracing (ours): 173 hours (4.6x) x64 Greedy Shell Tracing (ours): 155 hours (5.2x) 39

METHODS OVERVIEW Low order High order Moon et al. 2007: Explicit Path Tracing Shell Tracing - Per-grain material precomputation - Only homogeneous Meng et al. 2015: Volumetric PT + Diffusion Explicit Path Tracing - Per-grain type precomputation - Only homogeneous & monodisperse Ours: ✓ ✓ (Explicit PT + ) Proxy PT Volumetric Shell Tracing - Per-grain type precomputation - One-time global precomputation 40

OUR FULL METHOD VS. MENG ET AL. 2015 (HOMOGENEOUS) Meng et al. 2015 Our full method Explicit Path Tracing 93 hours (145x) 5 hours (2,696x) 13,480 hours 41

OUR FULL METHOD VS. MENG ET AL. 2015 (HOMOGENEOUS) Relative Squared Error x8 Meng et al. 2015 Our full method Explicit Path Tracing 93 hours (145x) 5 hours (2,696x) 13,480 hours 42

OUR FULL METHOD VS. MENG ET AL. 2015 (HOMOGENEOUS) Explicit PT (reference) 13,480 Explicit PT (reference) 13,480 hours hours Meng et al. 2015 93 Our full method 5 hours hours 43

OUR FULL METHOD VS. MENG ET AL. 2015 (HOMOGENEOUS) Explicit PT (reference) 13,480 Explicit PT (reference) 13,480 hours hours Meng et al. 2015 93 Our full method 5 hours hours 44

OUR FULL METHOD (HETEROGENEOUS) 45

MORE RESULTS AND VALIDATION 46

MORE RESULTS AND VALIDATION 47

LIMITATIONS OF BOUNDING SPHERE PACKING • Limited packing density • No anisotropy • Uncorrelated grain orientations [Meng et al. 2015] 49

FUTURE WORK FOR VOLUMETRIC SHELL TRACING • Shell Tracing vs. Diffusion • Shell Tracing in clouds • Hair rendering 50

THANK YOU FOR YOUR ATTENTION! Email: muelltho@inf.ethz.ch Web: https://tom94.net ACKNOWLEDGEMENTS - Maurizio Nitti - Alessia Marra - Romain Prévost - Stanford 3D Scanning Repository