Sampling BSSRDFs with non-perpendicular incidence

نویسنده

  • Etienne Ferrier
چکیده

Sub-surface scattering is key to our perception of translucent materials. Models based on diffusion theory are used to render such materials in a realistic manner by evaluating an approximation of the material BSSRDF at any two points of the surface. Under the assumption of perpendicular incidence, this BSSRDF approximation can be tabulated over 2 dimensions to provide fast evaluation and importance sampling. However, accounting for non-perpendicular incidence with the same approach would require to tabulate over 4 dimensions, making the model too large for practical applications. In this report, we present a method to efficiently evaluate and importance sample the multi-scattering component of diffusion based BSSRDFs for non-perpendicular incidence. Our approach is based on tabulating a compressed angular model of Photon Beam Diffusion. We explain how to generate, evaluate and sample our model. We show that 1 MiB is enough to store a model of the multi-scattering BSSRDF that is within 0.5% relative error of Photon Beam Diffusion. Finally, we present a method to use our model in a Monte Carlo particle tracer and show results of our implementation in PBRT.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Principles of Appearance Acquisition and Representation ICCV 2007 Short Course

Algorithms for scene understanding and realistic image synthesis require accurate models of the way real-world materials scatter light. This course describes recent work in both the graphics and vision communities to measure the spatially-and directionally-varying reflectance and subsurface scattering of complex materials, and to develop efficient representations and analysis tools for these da...

متن کامل

COMPARISON OF INCIDENCE AND GRADE OF PRESSURE ULCER IN SMOKERS AND NON-SMOKERS ADMITTED TO INTENSIVE CARE UNIT

Background & Aims: Pressure ulcer is a serious problem in patients admitted to the intensive care unit. It is associated with major complications such as prolonged length of stay and delayed recovery. The aim of this study was to compare the incidence and grade of pressure ulcers in smokers and non-smokers admitted to the intensive care unit. Materials & Methods: This study is an analytical cr...

متن کامل

Noninvasive imaging of 3D micro and nanostructures by topological methods

We present topological derivative and energy based procedures for the imaging of micro and nanostructures using one beam of visible light of a single wavelength. Objects with diameters as small as 10 nm can be located, and their position tracked with nanometer precision. Multiple objects distributed either on planes perpendicular to the incidence direction or along axial lines in the incidence ...

متن کامل

Simultaneous unbiased estimates of multiple downed wood attributes in perpendicular distance sampling

Perpendicular distance sampling (PDS) is a fast probability-proportional-to-size method for inventory of downed wood. However, previous development of PDS had limited the method to estimating only one variable (such as volume per hectare, or surface area per hectare) at a time. Here, we develop a general design-unbiased estimator for PDS. We then show how that estimator can be used to develop s...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • CoRR

دوره abs/1609.02072  شماره 

صفحات  -

تاریخ انتشار 2016