“Contrast Displays: An Interactive Haptic and Visual

Interface for Mesh Quality Analysis”

Lisa Durbeck, M.S. C.S.Thesis

Reproduced with permission from http://www.scs.leeds.ac.uk/cpde/knock.html

3D unstructured tetrahedral mesh

Process

My Interface

16,000-element mesh,16,000 error values

How good is this mesh?Where are the bad elements?

Why are they bad?

Approach:

• reduce mesh to a handful of elements

• interaction model is compare/contrast

• compare geometry, compare error level

• visual comparison info: color, shape

• haptic comparison info: texture

• provide analytic information in a Closeup view

• what matters: size, shape, orientation of tet. and its neighbors

colors

0.02 - 0.03

0.01 - 0.019

0.0 - 1e-6

geometrical considerations: shape, size, location, face orientation

force feedback

force

0.16

-0.16 Distance: 0 to 6 cycles/mm

comparative information

High Level:Mesh Geometry

Why are they bad? Present Spatial Distribution ofError as movie

Local Level: tetrahedronerror is a function of

Local View centered about aparticular tetrahedron

shape Drawing Tets as Solids

shape Exploded View

size do nothing

orientation rotation of Exploded View

orientation Displaying Axes

error at neighbors showing neighbors

error at neighbors providing control of coloring

error at neighbors rotations of exploded view

Depends OnQuestion Interface to Question

Problem/SolutionMesh Geometry

Where are the worst meshtetrahedra?

Present Spatial Distribution oferror as movie

Global view with User-Controlled Subsetting in the

error domain

Default to worst 2% oftetrahedra

order via color, texture map

Software System Development

HAPTICS

GRAPHICS

ADAPTIVE MESHGENERATION

ERROR ESTIMATION

INTERPROCESSCOMMUNICATION

TETRAD

TETRAD

SCIRun

SCIRun, GHOST SDK

C