Rapid Visualization of Geological Concepts · Conformal map to assign illustrative texture that...

Rapid Visualization of Geological Concepts

Mattia Natali 1, Ivan Viola 1,2, Daniel Patel 2,1

1 University of Bergen (UiB), Norway 2 Christian Michelsen Research (CMR), Bergen, Norway

08/10/2012

● Create the 3D illustrative models found in geological text books

● A way for geologists to express and explain processes involved in the

subsurface

• Sketch-based interface to rapidly obtain geological illustrations

Introduction

2 / G. Thompson and J. Turk [1]

- Mattia Natali -

08/10/2012

● Structural geology is the study of the three-dimensional distribution of

rock units with respect to their deformational histories

● Illustrative visualization in geology:

Illustrative Geological Models

3 /

Teaching purpouses Communication between experts

[John Koonz] [Haakon Fossen]

- Mattia Natali -

08/10/2012

● Importance of communicating abstract ideas ('visual thinking')

● Expressiveness

● Show and explain how earth has behaved or will behave

● Self-descriptive notation

Motivation: Geological Illustrations

4 / Courtesy of Haakon Fossen [2]

- Mattia Natali -

08/10/2012

● Intuitive for non-experts (geologists who are not illustrators)

● Does not require many hours to build a model

● Reduce quantitative details in favour of simplicity and rapidity,

replacing the use of parameters with free-form user strokes

● Covers the need for a rapid modelling tool in geology

● Few methods applied to geological field

5 /

Motivation: Sketch-based Technique

- Mattia Natali -

[James Geikie]

08/10/2012

? geology

architecture

Sketching Geology

6 / - Mattia Natali -

08/10/2012

● Combine sketching approach with illustrations in a specific domain

Contribution

7 /

G. Thompson and J. Turk [1]

- Mattia Natali -

08/10/2012

Sketch-based Process

• Build a layer-cake visualization, showing the internal stratigraphy

of the subsurface

8 /

● Interpret such drafts and generate an illustrative model

[USGS]

- Mattia Natali -

08/10/2012

● Fold: deformation of an originally flat layer

(usually produced by a sedimentation process),

that has been bent by forces acting in the crust

of the earth

● Fault: originates when forces that act on a

● specific layer are so strong that they overcome

●the rock’s elasticity and yield a fracture

● Foot and Hanging Wall:

Fold & Fault


08/10/2012

Workflow


08/10/2012

● Sketch acquisition on a cross-section view

● Each curve defines a horizon (surface obtained by

extrusion)

● Two adjacent horizons identify a layer (rock type)

● Construction of a layer-cake model

● Texture application (adapting to the shape of a layer)

● Guided texture (when necessary, depending on the kind

of geological process)

● Context and notation addings

Description of the Process


08/10/2012

● Each sketch acquired as ordered set of points

● Constrained Delaunay triangulation (2D)

● Mesh refinement (1-to-4 triangles)

● Texturing through conformal map

Fold Specification


08/10/2012

● Each fault applies on one or more layers (couples of piece-wise linear

curves) and it is defined by:

● 1. Fault trace

● 2. Direction of the forces involved in the process

Fault Specification


08/10/2012

● Conformal map to assign illustrative texture that maintains its

expressiveness and meaning (according to a legend or standard

symbols in structural geology)

● Angles preservation minimizing a functional that takes in

consideration changes from the domain to the image space of the

texture map

● Guided texture

● Projected drawings

Texturing

14 / Courtesy of Graham R. Thompson [1] - Mattia Natali -

08/10/2012

● The sketch which guides the texture in a new shape is cloned

● The pair of curves is placed such that it incorporates the entire layer

● Conformal mapping for the outermost twin curves

● Extraction of the texture from the inside of the layer

Guided Texture


08/10/2012

● Some examples with the various situations that can be represented

Results I


08/10/2012

Results II

17 /

● Multi-fault and oceanic crust examples

- Mattia Natali -

08/10/2012

Time Comparison

Model definition and non-optimized rendering

18 /

Illustrator's estimation(using Adobe Illustrator)

~ 2 min

~ 1 min

~ 1 min

~ full day

~ 1-2 hours

~ 1 hour

- Mattia Natali -

08/10/2012

Conclusions

● Just folds and faults are able to cover a large amount of situations and

behaviours occurring inside the crust of the earth

● Fast and intuitive interaction for the user

● Illustrative geology, from text-books to 3d digital models

● Sketching in a specific domain to adapt the technique to well-defined

constraints


Thompson and Turk [1]

08/10/2012

● Widen the model with more geological events (salt domes, deltas,

channels, etc...)

● Provide physical simulations, like erosion or flowing fluid

● Animated illustrations (in progress)

● Impose geo-physical constraints

20 /

Future Work

- Mattia Natali -

08/10/2012

Thank you for your attention!

References:

● [1] G. Thompson and J. Turk, Introduction to physical geology, ser. Saunders Golden Sunburst

Series. Saunders College Pub., 1998.

● [2] H. Fossen, Geologi. Stein, mineraler, fossiler og olje. Fagbokforlaget, 2008.


This work is part of the GeoIllustrator project. Our acknowledgement goes

also to Haakon Fossen, Graham R. Thompson and the reviewers

Rapid Visualization of Geological Concepts · Conformal map to assign illustrative texture that...

Documents

Transcript of Rapid Visualization of Geological Concepts · Conformal map to assign illustrative texture that...