caad futures 2015: development of high-definition virtual reality for historical architectural and...

July 9, 2015

Tomohiro Fukuda*1 Hirokazu Ban*2

Katsuhito Yagi*3 Junro Nishiie*2

1

Development of High-definition Virtual Reality for Historical Architectural and Urban Digital Reconstruction- A Case Study of Azuchi Castle and Old Castle Town in 1581 -

*1 Osaka University, Osaka, Japan

*2 Omihachiman City Government, Shiga, Japan

*3 Toppan Printing Co., Ltd., Tokyo, Japan

Contents

1. Introduction

2. Development of High-definition Virtual Reality Application

3. Validation of Qualitative Method

4. Quantitative Investigation

5. Conclusion

2

3D Visualization in architectural and urban fields

Experience and understand 3D virtual space intuitively

Began with the pre-rendering technique to create 3DCG image and animation

NTSC (640*480 px), 30 frames/sec, 30 min. to generate a frame3

1. Introduction -1

”Osaka” (1983), Sasada lab., Osaka-U

Real-time rendering technique (VR. 1/30-1/60 sec. to generate a frame)

Gives users to interact with 3DVE: Walk-through, comparison of design alternatives,

dynamic simulation in real time

Become common in the use of PCs

Problems of VR for arch. and urban use

Number of defining objects is large; Objects from a small scale to a huge scale is handled at

the same time -> Difficult to render in real-time with high accuracy and realism

▶ Texture mapping instead of geometry, Culling

▶ Level of Detail (LOD) to change 3D models and textures to depend on the distance from VR

camera 4

1. Introduction -2

VR screen capture Shimonoseki prj. (2010)

Previous Studies about VR application

Future simulation at design stage

Digital archiving of existing and past architecture and townscapes

►Studies to construct a detailed realistic VR using recent advances in the

PC environment have not been reported

5http://en.wikipedia.org/wiki/File:%E5%AE%89%E5%9C%9F%E5%9F%8E.jpg

Azuchi-jō-zu, a drawing of the castle

1. Introduction -3

Research Purpose

Show fundamental data to construct a high-definition VR application

Target: VR restoration of Azuchi Castle and its old town

Wide-area architectural

and city objects

For the NEXT CITY:

Rediscover, Revitalize,

Renovate mature society

combining with new

technology

Collaborative project

between local

government, research

scientists and VR

creators

Contents

1. Introduction




5. Conclusion

6

2.1. Target

Azuchi Castle (Omihachiman city, Shiga, Japan Built by Oda Nobunaga in 1579, Destroyed after Honnoji Incident in 1582

Located on the shores of Lake Biwa

Keep tower: 40 m high, Buildings and stone walls of the castle: built over the

whole area of Mt. Azuchi (110 m high)

Castle town: built at the foot of Mt. Azuchi

7


Mt. Azuchi

Lake Biwa

Reconstruction of stone steps and walls

after archaeological dig

Oda Nobunaga Toyotomi HIdeyoshi Tokugawa Ieyasu Honnoji Incidenthttps://ja.wikipedia.org/wiki/%E8%B1%8A%E8%87%A3

%E7%A7%80%E5%90%89#/media/File:Toyotomi_hidey

oshi.jpg

https://ja.wikipedia.org/wiki/%E5%BE%B3%E5%B7%9D%E5%

AE%B6%E5%BA%B7#/media/File:Tokugawa_Ieyasu2.JPG

https://ja.wikipedia.org/wiki/%E7%B9%94%E7%94%B0%E4%BF%A1%E9%95%B7#/media/File:Honnoj.jpg

2.1. Process of developing VR

8


1) Survey and planning

2) Scenario scripting

3) Data collection and analysis

4) Texture generation

5) 3D data modeling

6) Programming and visual effects

7) BGM, sound effect and narration

8) Integration and final adjustment

3) A part of full-scale Keep tower

for Sevilla EXPO 1992

5) Keep tower

5) Buildings for the castle

5) Terrain and castle townMeeting

2.2. Materials for the VR reconstruction -1

Whole

Record books, Excavation reports

Illustrations in the late 16th century

Azuchi Castle

Keep tower: Restoration plan by Dr. Naito Akira

Honmaru palace and Hideyoshi house: 1:40 scale model and

drawings

Turrets and gates: Deduced from excavation reports, from

existing castles of the same era, and from the architectural

style of that time

9


1:20 scale model of keep tower 1:40 scale model of Hideyoshi house

Luís Fróis, Nihonshihttps://ja.wikipedia.org/wiki/%E3%83%AB%E3%82%A4%E3%82%B9%E3%8

3%BB%E3%83%95%E3%83%AD%E3%82%A4%E3%82%B9#/media/File:Nih

onshi.jpg

2.2. Materials for the VR reconstruction -2

Old Castle Town

Roads, temples and shrines: Deduced by using old maps before modernization

Houses and people’s lifestyles: Deduced from materials of the same period such

as Rakuchurakugaizu

Terrain

Over a 65km square range including Lake Biwa

Resolution: 5km square in the center part: 1m mesh | Another area: 30m mesh

10


Rakuchurakugaizu Terrain model

Mt. Azuchi

Lake Biwa

Kyoto

https://ja.wikipedia.org/wiki/%E6%B4%9B%E4%B8%AD%E6%B4%9B%E5%A4%96%E5%9B%B3#/media/File:%E6%B4%9B%E4%B8%AD%E6%B4%9B%E5%A4%96%E

5%9B%B3%E5%B7%A6.jpg

Flat tiles (74,000 polygons)

Round tiles

(168,000 polygons)

2.3. Level of Detail -1

3D Modeling Stage

To represent high-definition VR: Detailed elaboration polygons and high-resolution

texture generation Disadvantageous for real-time rendering Application of LOD

11


Roof Tiles of Keep Tower

Roof Tile Model of Keep Tower

Major elements to represent an architectural façade Increase data amount when

roof tile objects were repeatedly used

Depending on the distance

of the VR camera from the

center of keep tower

0-50m: Both flat tile and

round tile were rendered

50-100m: Round tile was

linearly faded out

100m beyond: Only the

flat tile was renderedFlat tiles

(74,000 polygons)

Round tiles

(168,000 polygons)

2.3. Level of Detail -2

Terrain Texture Mapping

Mapped repeatedly to represent a wide range efficiently

When terrain is viewed from the sky, this repetitive representation becomes

apparent If the texture is not mapped repeatedly, necessary to reduce the texture

size Impossible to obtain sufficient resolution for closing up

Depending on the distance of the VR camera from the terrain model

0-20m: Not rendered repeatedly

20m beyond: Rendered repeatedly

12


0-20m 20m beyond

2.4. Representation of Natural Objects -1

Natural Objects

Curved surfaces are present, Repeating texture is difficult

▶ Disadvantageous for real-time rendering

Stone Walls

Used some existing stone walls in Azuchi Castle as texture

Stone wall of the base of the keep in close proximity: 3D

polygons of the stone wall were created to enhance reality

13


Traditional method

Proposed method


Shade and Shadow

Applied IBL (Image Based Lighting) technique to wide area and four time zones

(morning, afternoon, evening and night) Texture of the sky: Created HDR by combining more than 600 photos at Azuchi

Blended shadow data generated by shadow mapping technique with texture

materials

14



Lighting

Beams of sunlight shining: Used a volume metric lighting

Controlling light intensity to soften the degree pf penetration of sunlight in

response to the angle between VR camera and the sun’s rays

15



Reflection of Water Surface

Texture of a mirrored image which was produced by off-screen rendering

technique, and a normal map created from the height map of waves, were

blended

16



Settlements in the old Castle Town

Inefficient to make and set more than 1000 houses one by one

▶ Objects such as houses, gardens and roads were created

▶ The objects were placed at random using procedural modeling techniques

17


2.5 Developed High-Definition VR Application

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3D modelPolygons 7.86 million

Vertices 6 million

Texture

Textures 1000

Texture pixels 1.87 billion

Data amount 3 GB

VRAM use when running VR 6.27 GB

Total systemData amount 7 GB

Frame rate 30-60 fps

Short Movie Mode:

15-minutes captured VR movie

is set against the backdrop in

1581

Manual Mode:

Controller facilitates free

movement within the virtual

Azuchi Castle interactively and

seamlessly

Specification of the developed VR application

2.5 Main shots of the VR short movie

19


20

VR Azuchi Castle screen capturehttps://www.youtube.com/watch?v=QnnVxMNiZo0

Contents

1. Introduction




5. Conclusion

21

3.1. Methodology

Subjects: Three VR creators

(30s male, 30s female and 20s female)

Subjects described the pros and cons of

the representative VR scene by referring to

the evaluation items

Full view: included all of Azuchi Castle, the

old castle town and terrain (Time zone: 3)

Keep tower view (Time zone: 3)

Castle town view: looked at the old castle

town (Time zone: 3)

Main road view: looked up at the keep tower

from the main road (Time zone: 4)

22


PC spec PC model HP Z820 Workstation

OS Windows7 Professional 64-bit

CPU Intel Xeon E5-2643 v23.5GHz

Main

memory

64GB

Graphics

board

NVIDIA Quadro K6000 (VRAM:

12GB

Display Resolution 1920x1080

PC specifications

Factor Element Evaluation items

3D

modelingShape

Outline

Surface

Detail

Extensiveness

Rendering

LightingLight source

Color shade

Shade and

shadow

Shade

Shadow

Material

Color

Pattern

Texture

DepthFocus

Haze

Scene Natural scene

Image qualityColor

Aliasing

Expressing

Image

synthesis

Color

Outline

Composition

Staffage

Staffage

Scale

Perspective

Garnish

Time

Motion

Effect

Output

Condition

Dimension

Effect

3.2. Result and discussion – Full View

Positive (N=8): Integrated set of VR

images was realized.

Negative (N=4): Green texture

rendered in Mt. Azuchi was

unnatural.

23


3.2. Result and discussion – Keep tower View

24


Positive (N=8): Azuchi Castle model

was represented in detail

Negative (N=8): A part of the

daytime scene showed inconsistency

between shade and shadow.

Shade and shadows should be

calculated integrally based on the

physical quantity of light and

material properties, but wide area

real-time rendering techniques, it is

hard to apply the global illumination

technique.

Then, the shade data by IBL and the

shadow data by shadow mapping

had to be defined separately and

integrated.

3.2. Result and discussion – Castle town View

25


Positive (N=4): Modeling quality of

the houses was high.

Negative (N=13): Liveliness of the

castle town could not be observed.

Vario-items such as people, small

animals and store curtains should

be placed in the old castle town to

add liveliness.

But, they were placed manually with

much labor and expense.

3.2. Result and discussion – Main road View

26


Positive (N=7): Roof tiles and stone

walls were expressed realistically.

Negative (N=3): Consistency of the

sky and lighting were insufficient.

Real photos were used as textures of

the sky and wall stones. But, buildings

were calculated using CG on the PC as it

no photos existed. The inadequate

consistency resulted from this reasons.

Contents

1. Introduction




5. Conclusion

27

4.1. Methodology

Subjects: End-users (N=286)

Subjects viewed both short movie and manual modes, they

responded to the evaluation after the symposium held in March

and May 2014

Questionnaire items were answered using Likert five-point

agree/disagree scale

28


VR experience by end-users

4.2. Result and discussion

Developed VR: “Very good”

and “Good” of respondents

accounted for 88% of

responses.

High-definition VR experience

of the old Azuchi Castle and its

castle town: “Very interesting”

or “Interesting” of respondents

accounted for 89%.

The developed VR application

received a very positive

evaluation by end users.

29


About the developed VR application (N=286)

About High-definition VR experience (N=286)

Contents

1. Introduction




5. Conclusion

30

5. Conclusion

To perform 3D-VR real-time rendering with high resolution, accuracy and realis, both LOD and representation techniques of natural objects and phenomena were developed, and the VR application of Azuchi Castle and its old town was constructed by integrating them.

Through the qualitative and quantitative evaluations, the developed VR obtained a certain number of positive judgments. Problems to be solved such as shade and shadow, and lively representation of the castle town were also clarified.

This VR system will be used for tourism, education and civic pride.

31New theater for VR Azuchi Castle (April, 2015)Azuchi Castle Remains

32

Acknowledgements

We thank all the participants for their generous assistance in

conducting Azuchi Castle VR project and experiment.

Obrigado!

caad futures 2015: development of high-definition virtual reality for historical architectural and...

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