Direct Volume Rendering wShading via Three Dimensional Textures

Direct Volume Rendering w/Shading via Three. Dimensional Textures

Introduction n Intro Limitations Other methods

Overview of Texture-Map n n n Initial step Lookup table computation Texture map processing

Ambient Light n Calculation

Reflecting Surface Classification n Calculation

Reflected Light Component n n Half-way vector specularity model Lambertian diffuse shading

Gradient Quantization n Quantize gradient direction Unit Sphere Tessellation

Rendering Slices n n Apply texture Back to front ordering

Texture Coords n n Bounding cube Transformation:

Alternative Pipelines

Results

Footprint Evaluation for Volume Rendering

Introduction n n Forward-Mapping Algorithm Overview

Previous Work n n n Ray tracing Compositing techniques Fitting surfaces into data cells

Rendering Algorithm n n Differences from original algorithm Algorithm breakdown q q n Transforming Shading Reconstruction Visibility Splatting

Footprint Function n Calculate once for each view

Generic Footprint Table n n Spherical Kernel Integration along the Z axis

Extents and Mapping n Two cases

Extents and Mapping (cont. ) n Extent n Mapping n Ellipsoid defined as

Table Sizes and Kernels n 3 Parameters q Size of the table n Space vs. Quality tradeoff q Accessibility of the table q Table’s underlying kernel

Table Sizes and Kernels (cont. )

Sample Images

Sample Images (cont. )