wood carving simulator

Haptic Enabled Virtual Wood Carving

INDEX

1. Organizational Overview........................................................................................................2

2. Profile of the Problem..............................................................................................................5

3. Existing system.........................................................................................................................7

4. Problem Analysis.....................................................................................................................8

4.1 Product Definition...............................................................................................................84.3 Product Plan.......................................................................................................................10

5. Software Requirment Specification(SRS)............................................................................11

6. Software Design Document(SDD)........................................................................................26

7. Project Legacy........................................................................................................................35

9.1 Current Status of the project..............................................................................................359.2 Remaining Areas of Concern.............................................................................................35

8. User Manual...........................................................................................................................36

9. Abbreviations and Glossary..................................................................................................39

10. References...............................................................................................................................40

1


Organization Overview

Introduction

For most of India’s population, viable employment remains out of reach: 90 percent of

the work force is employed in informal, low-productivity jobs like daily wage labor, ad-

hoc plumbing, and brick laying.

This is not for lack of demand for skilled labor—as India’s economy booms, along with it

the need for skilled workers is high and rising. But vocational education and training

institutes have become a bottleneck: facing budget constraints and inadequate numbers of

trainers and materials, these traditional academic structures have been unable to keep up.

With its revolutionary application of haptic technology and multimedia, S.A.V.E is

opening the floodgates, demonstrating the means to provide vocational education on a

broader scale than ever seemed possible using traditional methods. And by targeting

individuals who have thus far been sidelined in India’s economic progress, S.A.V.E’s

work offers concrete proof that with proper application of modern technology, prosperity

and growth are increasingly achievable for all sectors of society.

Objective

Sakshat Amrita Vocational Education (s.a.v.e) aims to provide economically

marginalized populations with the opportunity to positively alter their employment

circumstances. Through its revolutionary approach to vocational education using cutting-

edge haptic technology and multimedia-enriched computerized training programs,

S.A.V.E is breaking down traditional logistical barriers to educating remote and

2


impoverished communities, and charting a course toward offering vocational education

on a scale never before possible.

S.A.V.E strives to:

Enhance the employability of the illiterate and semi-literate sections of society throughout

India.

Broaden the scope of existing vocational education and training institutes.

Accelerate the learning process via advanced technologies including haptics and

interactive multimedia tools.

Raise the standard of education, thus infusing the labor market with skilled and

productive workers/artisans who can earn a living wage and raise the standard of living in

their communities.

Scope

S.A.V.E harnesses the power of cutting-edge technology to extend vocational training

courses specifically to individuals and communities who—due to traditionally

insurmountable logistical and cultural barriers—have been long been left on the sidelines

of India’s economic progress. The revolutionary application of haptic technology and

multimedia renders limitless the potential reach of S.A.V.E. With multilingual support,

web-based user interface and low-cost, light-weight haptic technology replacing heavy-

duty tools and machinery, S.A.V.E is poised to shatter conventional limitations in

providing vocational training on a broad scale to some of India’s least-served populations.

3


Universalizing Education

S.A.V.E caters to a population that until now has been disproportionately handicapped in

their ability to enter into effective income-generating activities: illiterate, semi-literate

and individuals with limited education. S.A.V.E courses will be available in every major

Indian language and in English, guaranteeing that S.A.V.E can be effective nationwide.

Connectivity

With S.A.V.E courses accessible from anywhere where there is Internet or satellite

connectivity—desktop and laptop computers, standard mobile phones and smart-phones

—location will no longer be a barrier to vocational education. S.A.V.E courses can be

transmitted to remote locales, equipping these vulnerable communities with the skills and

means they need to survive and prosper in a changing world.

Low Cost Infrastructure

The unique application of haptic technology to vocational education will minimize the

need for materials and tools. Individuals will gain the experience of ‘working’ on

expensive equipment without risking damage, wear and tear. Additionally, the

accessibility of S.A.V.E further minimizes required infrastructure.

4


Profile of the problem

Introduction

The ancient Indian art and techniques of wood carving & carpentry are slowly dying. The

reasons are varied, from the long time it takes to become master the skills & techniques

involved to the lack of suitable markets. SAVE (Sakshat Amrita Vocational Education) at

the Amrita E-learning Labs intends to create a software and hardware system that will

capture the look and feel of working on real wood and then use this to record and teach

our traditional techniques of wood cutting and carving. My project will be the first step in

this direction by modeling a virtual wood that will emulate the look and feel of real wood

using advanced 3D graphics and haptics technologies. This project has inputs from the

Amrita Shilpa Kalakshetram in Trivandrum.

2.2 Objective and scope of project

The ancient Indian art of woodcarving is slowly dying because of the lack of students and

The opportunities are still attractive since handmade wood sculptures fetch tens of

thousands of rupees in the market. But due to the fact that schools that teach this ancient

art are few and masters of wood carving are hard to find these days, these traditions are

slowly being lost. Bringing haptics into this area serves two purposes:

Preserving a very important part of our culture by enabling the transmission of

techniques down the generations with the help of a Virtuo-Haptic immersive

environment.

Provide opportunities for the thousands of talented yet unemployed youth in India.

5


Provide hobbyists with the means to learn the art of woodcarving without

significant investment in wood, sculpting tools and tutors.

In parallel there is another team in SAVE that is working to make hardware that will give

the feel and feedback of real world wood sculpting tools. Presently I will be using a 3

degrees of freedom (movement and feedback) device, the Novint falcon to develop the

software. Although this device will not be suitable in the long run, it will be useful in

developing the haptics and graphics algorithms that will simulate the look and feel of real

wood.

6


Existing Similar Systems

No similar systems exist in this field at all. The most similar systems to haptic woodcarving

are the various bone drilling applications developed in Stanford University.

7


Problem Analysis

The ancient Indian art of woodcarving is slowly dying because of the lack of students

even though the opportunities are still attractive since handmade wood sculptures fetch

tens of thousands of rupees in the market. But due to the fact that schools that teach this

ancient art are few and masters of wood carving are hard to find these days, these

traditions are slowly being lost.






wood.

4.1 Product definition

The virtual wood carving application is a part of the SAVE initiative (Sakshat Amrita

Vocational Education), an ongoing project of the Amrita E-learning Research Labs.

SAVE intends to virtually train millions of people in vocations that require trained skill

sets. Wood carving which requires hours of practice is an ideal application of haptics and

virtual reality

8


Importance and benefits:

The haptic wood carving application will be helpful in preserving our ancient

heritage by creating a skeleton application into which we can record the wisdom and

skills of the masters. There is also an employment aspect to it as woodcarving can be

mastered faster using a haptics application and highly skilled artisans can earn a lot of

money.

9


4.2 Project Plan

Modeling Virtual Wood

Sl. No Name of module Description of module Estimated work (days)

1 Algorithm 1 This is where the algorithm for isosurface extraction is determined

30

2 Implementation 1 Implementing Marching Cubes to model virtual wood

20

Total days: 50

Carving

Sl. No Name of module Description of module Estimated work (days)

1 Database design Localized Marching Cubes to for carving virtual wood

20

2 Database (sec: 1) Mesh deformation for carving

10

3 Database (sec: 2) Interactive viewing 104 Database (sec: 3) Pencil drawing 5

Total days: 45

10


System Requirements Specification

1. Introduction

1.1Purpose

The purpose of this document is to detail the requirement specifications for a Haptics

Enabled Virtual Wood Carving application. The ancient Indian art and techniques of

wood carving & carpentry are slowly dying. The reasons are varied, from the long time it

takes to become master the skills & techniques involved to the lack of suitable markets.

SAVE (Sakshat Amrita Vocational Education) at the Amrita E-learning Labs intends to

create a software and hardware system that will capture the look and feel of working on

real wood and then use this to record and teach our traditional techniques of wood cutting

and carving. My project will be the first step in this direction by modeling a virtual wood

that will emulate the look and feel of real wood using advanced 3D graphics and haptics

technologies. This project has inputs from the Amrita Shilpa Kalakshetram in

Trivandrum.

1.2Project Scope






11


Preserving a very important part of our culture by enabling the transmission of techniques

down the generations with the help of a Virtuo-Haptic immersive environment.


Provide hobbyists with the means to learn the art of woodcarving without significant

investment in wood, sculpting tools and tutors.






wood.

12


Overall Description

1.3Product Perspective





virtual reality

13


1.4Product Features

Models properties of actual wood as realistic as possible both visually and haptically.

Allows the student to feel the texture and shape of wood sculptures and wood pieces.

Provides basic wood carving lessons.

The software detects errors in the basic carving lessons and alerts the student.

14


1.5User Classes and Characteristics

Students

o Students new to the field of sculpting will use this software to learn the basics of the

trade.

o Since the tool is designed for the use of students of sculpting primarily, it is important

that I gauge their comfort with using computers.

Expert Instructors

o Experts in the field of wood carving will evaluate the software and give feedback which

will go onto making the software more effective.

o Of particular interest will be in comparing real world teaching techniques with virtual

ones.

SAVE team members

o Other developers on the SAVE team will also evaluate the software. They will be

interested in seeing how the software fits into the overall scheme of things at SAVE.

1.6Operating Environment

Hardware Environment

A system with minimum 2GB RAM and a multicore processor with speed >2 GHz

15


A medium or high end GPU for graphical processing.

A sound card.

A Three Degrees of freedom (3-DOF) haptics device like the Novint Falcon. 6 DOF

devices like the Sensable Phantom are preferred.

Software Environment

Windows Vista or Windows 7 as the OS.

CHAI3D Graphics/Haptics scenegraph library.

Novint Falcon drivers.

OpenAL and/or BASS audio libraries.

Visual Studio 2005 or 2008.

Virtual haptic device

1.7Design and Implementation Constraints

One particular constraint of this project is that a wood carving tool would need a 6 DOF

device. However the haptic device available for SAVE is the Novint Falcon which is a

3DOF device.

There is a need for a medium to high end graphics card onboard the computer since the

graphics in the application will be demanding.

1.8Assumptions and Dependencies

Assumptions:

16


Accurate representation of an anisotropic material like wood will be possible through voxels and

the forces calculated using them.

The lack of a 6 DOF haptic device would not affect the usability of the software significantly. 6

DOF devices are under development at SAVE and commercial ones will also be procured. But

since their timeline exceeds that of my available project time,

17


2. System Features

2.1Generation of Wood voxels

3.1.1 Description and Priority

The virtual wood will be represented as voxels (volumetric data) with each voxel

representing a point in space with associated texture, stiffness and other haptic properties.

Unlike volumetric data available from MRI scans for haptic surgery applications, there

are currently no publicly available MRI or other volumetric data sets to use in the

application.

Therefore my software will either dynamically generate its own voxel data or allow the

user to manually input in voxel data.

Priority for this module is not very high at the early stages of application development.

Initially all voxels will have uniform properties with which the haptic & graphic

algorithms will be tested. This module can be developed at a later stage.

3.1.2 Stimulus/Response Sequences

18


2.2Graphic rendering of the virtual wood


The wood volumetric data needs to be rendered by extracting surface voxel data into

isosurfaces that can be rendered as primitive triangles in OpenGL. I propose to use

Yarden Livnat and Charles Hansen’s method for isosurface extraction which is halfway

between CPU intensive ray tracing and GPU intensive Marching Cubes algorithm. For

graphics refresh rate to be maintained near 60 Hz it is important that the voxel access time

is constant or close to O(n) or lesser. The texture stored in each voxel will be queried to

display as corresponding colored triangles in OpenGL.

The priority of this module is very high since visual realism is important in a teaching

environment that places importance on visual inspection to judge the quality of the work.


19


2.3Haptic rendering of wood and sculpting tool


Haptic rendering is as important a critical activity as graphical rendering. It is important

to haptically capture the feel of carving into wood. Each voxel will have a haptic property

associated with it. Therefore the feedback force will be calculated from all the voxels

currently in contact with the sculpting tool. This done by calculating a negative force

depending on the vector of the chiseling tool, its incident force and the cumulative value

of the haptic texture property of all the voxels that the tool is touching (by taking an

average of all the friction parameters).

20



2.4Introductory lessons to wood carving


This module does not have very high priority value but nevertheless is intended to show

the utility of the whole application which will eventually be used as a tutor and one stop

place to learn everything about the Indian art of wood carving. This introductory part will

teach the student basic wood carving lessons like how to place the tool on the wood and

then perform some simple tasks like engraving a line, making pyramid shaped engravings

21


and some others with increasing complexity. This module will be completed only if the

time allows it.


22


3. External Interface Requirements

3.1Software Interfaces

CHAI3D Library : The open source CHAI (Computer Haptics & Active Interfaces) library is a Visuo-

Haptic library created by researchers at Stanford University. It’s a scenegraph library in which we

can define haptic and graphic properties for each object. Its written in C++. Graphics in CHAI3D is

using OpenGL and direct use of OpenGL primitives is also possible offering more flexibility than

other visuo-haptic libraries like H3DAPI.

Novint Falcon Driver : This is the software component that talks with the Novint falcon haptic

game controller. All interaction with the device is through this driver. CHAI3D provides a layer of

abstraction over this for the convenience of programmers.

Nvidia CUDA : An optional component at this stage, this might be used for storing voxels and for

speeding up graphical rendering since CUDA allows programmers to directly use the parallel

computing resources of the GPU.

23


4. Other Nonfunctional Requirements

4.1Performance Requirements

5.1.1 Computational Requirements

There are two parallel threads running in this application. One takes care of graphical

rendering while the other takes care of haptic rendering. The graphical rendering thread runs at

60 Hz while the haptic rendering thread runs at 1000 Hz since these are the rates at which

humans feel that the graphical or haptic feedback is realistic. But whatever be done, the haptic

thread should never slow down. Therefore care must be maintained not to burden the haptic

thread with tasks that are computationally heavy.

5.1.2 Processing Power

The application requires a mid-range graphics card and a fast processor since the

graphics for the application needs to be as realistic as possible. The points described earlier

under “computational requirements” also make the case for larger processing power, stronger.

24


Appendix A: Glossary

Haptics : Haptic technology, or haptics, is a tactile feedback technology that takes

advantage of a user's sense of touch by applying forces, vibrations, and/or motions to the

user.

CUDA: is a parallel computing architecture developed by Nvidia.

Voxel : A voxel (volumetric pixel) is a volume element, representing a value on a regular

grid in three dimensional space.

OpenAL : It is a cross-platform 3D audio API appropriate for use with gaming

applications and many other types of audio applications.

Degrees of Freedom : are the set of independent displacements and/or rotations that

specify completely the displaced or deformed position and orientation of the body or

system.

GPU : It is a specialized processor that offloads 3D graphics rendering from the

microprocessor.

25


Software Design Specification

1. Introduction

1.1 Purpose

The purpose of this document is to detail the design specifications for a Haptics Enabled

Virtual Wood Carving application. The ancient Indian art and techniques of wood carving

& carpentry are slowly dying. The reasons are varied, from the long time it takes to

become master the skills & techniques involved to the lack of suitable markets. SAVE

(Sakshat Amrita Vocational Education) at the Amrita E-learning Labs intends to create a

software and hardware system that will capture the look and feel of working on real wood

and then use this to record and teach our traditional techniques of wood cutting and

carving. My project will be the first step in this direction by modeling a virtual wood that

will emulate the look and feel of real wood using advanced 3D graphics and haptics

technologies. This project has inputs from the Amrita Shilpa Kalakshetram in

Trivandrum.

1.2 Scope






26


Preserving a very important part of our culture by enabling the transmission of techniques

down the generations with the help of a Visuo-Haptic immersive environment.


Provide hobbyists with the means to learn the art of woodcarving without significant

investment in wood, sculpting tools and tutors.






wood.

1.3 Reference Material

The US Dept of Agriculture’s “Wood Handbook”

“Visuohaptic Simulation of Bone Surgery for Training and Evaluation” by Christopher

Sewell et al.

“Voxel-Based Interactive Haptic Simulation Of Dental Drilling” by Jun Wua et al.

“CHAI: An Open-Source Library for the Rapid Development of Haptic Scenes”by

Francois Conti et al.

2. SYSTEM OVERVIEW

27






virtual reality.

28


3. SYSTEM ARCHITECTURE

3.1 Architectural Design

This diagram shows the overall design of the software and how each of the modules are

connected.

29


3.2 Decomposition Description

Here we go into the functional association between the different components.

30


4. COMPONENT DESIGN

4.1 UML sequence diagram of the CHAI3D virtual sculpting program

31


4.2 UML Activity diagram describing the Marching Cubes isosurface generating algorithm

32


These are the 14 different cases used for generating isosurfaces in the Marching Cubes method

33


4.2 UML Activity diagram describing Haptic rendering for the sculpting tool

34


Project Legacy

9.1. Current Status of the project

The system is currently partially complete. Work still needs to be done on the

localized marching cubes approach. The mesh deformation technique used currently

will be adapted for haptic carpentry lessons which require lesser precision and skill

than wood carving.

9.2. Remaining Areas of concern

Adaptive isosurface generation algorithms need to be used to smooth out the edges

while carving.

Octree based in the GPU is another feature to explore. This would lead to wood with

resolutions that is a thousand times more detailed than at present.

35


User Manual

Screenshots

Volumetric Virtual Wood

Drawing on the Virtual Wood

36


Carving on the virtual wood using Mesh deformation

Carving using localized marching cubes algorithm

37


Interactive Viewing

User options

Key ‘x’ – Close application

Key ‘r’ – Rotate virtual wood

Key ‘w’ – Wireframe show mode

Key ‘f’ – Fullscreen mode

Key ‘m’ – Use localized marching cubes

Key ‘p’ – Change tools (pencil to chisel and back)

38


Abbreviations & Glossary

Glossary

Haptics : Haptic technology, or haptics, is a tactile feedback technology that takes advantage

of a user's sense of touch by applying forces, vibrations, and/or motions to the user.

CUDA: is a parallel computing architecture developed by Nvidia.

Voxel : A voxel (volumetric pixel) is a volume element, representing a value on a regular grid

in three dimensional space.

OpenAL : It is a cross-platform 3D audio API appropriate for use with gaming applications

and many other types of audio applications.

Degrees of Freedom : are the set of independent displacements and/or rotations that specify

completely the displaced or deformed position and orientation of the body or system.

GPU : It is a specialized processor that offloads 3D graphics rendering from the

microprocessor.

39


References

The US Dept of Agriculture’s “Wood Handbook”

“Visuohaptic Simulation of Bone Surgery for Training and Evaluation” by

Christopher Sewell et al.

“Voxel-Based Interactive Haptic Simulation Of Dental Drilling” by Jun Wua et al.

“CHAI: An Open-Source Library for the Rapid Development of Haptic Scenes”by

Francois Conti et al.

40

wood carving simulator

Documents