Online Lecture 8

3D Digital Data Obtained Through Laser Scanning
Utilized in the Creation of Sculptural Reproductions

1. Introduction

Our laboratory has been gathering 3D digital data, obtained through laser scanning,since the 2004 academic year and studying how this can best be applied to our work.
Not only is the minute detail of shape and form obtained through laser scanning important in the compilation of records to aid the study of styles of Buddhist statuary, but also it is extremely useful when creating reproduction statues,an important
method of study that is carried out on a continuous basis in our laboratory.
This study of sculpture through reproduction also plays an extremely important role in the preservation and restoration of cultural properties; facilitating the understanding and transmission of classical sculptural techniques, improving of restoration
techniques, providing information on the current state of cultural properties, aiding preservation through the provision substitute statues for display and educating the public about preservation.
The laboratory utilized the 3D digital data obtained from our studies of Kofukuji temple's 'Ryutoki' and Todaiji temple's 'Seated Statue of Miroku' in the reproduction of these works

2. Characteristics of Laser Measuring

The laser scanner used in this project was a VIVID 900 which provides high-precision 3D data concerning the surface of the object scanned. One of the characteristics of data obtained through laser scanning in this way is that it is possible to achieve minute measurements of the smallest details and by combining the resultant 3D model with digital photographs, a natural 3D image can be created that may be viewed from any angle on a computer. Moreover, this combined data can be used to create transparent views, projections or contour-line plans with ease, which can then be rotated to any angled desired and printed out to provide accurate plans of every detail.
The following article describes how these characteristics can utilized in every stage of reproduction,creating new possibilities in the reproduction and exploring the
effectiveness of 3D digital data through actual use.

 3. Report on the Utilization of 3D Digital Data in the Reproduction of Statues

When reproducing a statue in the past, the sculptor relied on visual and photographic studies of the subject, this rough grasp of its shape and image representing the only preparation for the work and it was difficult to carry out an objective examination of the shape.
However, by utilizing the objective information provided by the 3D digital scanning, it has become possible to create much more accurate and efficient reproductions. The following is a report on the way in which 3D digital data has been utilized in the
reproduction of statues at our laboratory.

(1) Detailed Measurements Resulting from Laser Scanning Facilitates Waste-free Procurement and Preparation of Timber.Dimensions of Kofukuji temple's 'Ryutoki'measured with a VIVID 900 Laser Scanner (in millimeters)

   Overall Height: 1368.025
   Figure Height: 775.594
   Lantern Height: 415.782
   Cloud Height: 64.245
   Base Height: 137.798

   Figure Depth: 280.835
   Base Depth: 442.605
   Lantern Top Width: 333.604
   Lantern Top Depth: 292.095
   Lantern Base Width: 335.927
   Lantern Base Depth: 296.885
   Cloud Width: 274.268
   Cloud Depth: 272.215
   Distance From Top of Head to Chin: 161.804
   Distance from Ear to Ear: 156.011
   Width of Face: 120.121
   Depth of Head: 185.613
   Width of Shoulders: 284.815
   Depth of Chest: 187.004
   Width from Elbow to Elbow: 256.472
   Depth of Stomach: 206.486
   Width of Hips: 193.194
   Distance from Navel to Bottom of Base: 525.305
   Outer Width of Feet: 354.174
   Depth of Feet: 146.071
   Distance Between Inner Sides of Heels: 148.163
   Distance from Crotch to Bottom of Base: 351.130
Kofukuji temple's 'Ryutoki' Statue: 3D Image
Kofukuji temple's 'Ryutoki'
with Figure Removed: 3D Image
 Kofukuji temple's 'Ryutoki'
Dismantled: 3D Image

(2) By pasting the projection view created through 3D digital data directly onto the wood, it is possible to carry out the rough sculpting quickly and accurately. Moreover, when combining wood to create the basic structure of the statue using the 'yosegi- zukuri' technique, a projected view can be transferred to the center seam area,creating a clear standard outline that will not disappear as the sculpture progresses. 
Projection view of Todaiji temple's
'Seated Statue of Miroku'
Utilizing the projected
 view to carry out a rough sculpture of
Todaiji temple's 'Seated Statue of Miroku'

The cross-section plan
is transferred onto the
wood on the inner side
(where the two halves join)

The sculpting is carried
out using the
cross-section as a guide

Median cross-section of Kofukuji temple's 'Ryutoki' statue
Central seam of the reproduction of Kofukuji
temple's 'Ryutoki' statue

(3)The 3D model can be rotated through 360 degrees when it is viewed on a computer. This makes it possible to check details that are difficult to observe by eye.
Todaiji temple's 'Seated Statue of Miroku' 3D image
Kofukuji temple's 'Ryutoki' statue 3D image

(4)The contour-line plan created from the 3D digital data can be used to cut sections
  from thick boards, thereby creating a simple model that provides a sense of volume
  which cannot be achieved on the computer screen. 
A contour-line plan of the Todaiji temple's
'Seated Statue of Miroku' in a 5 mm. pitch
Work being carried out to create
a simple 3D model
Partway through the creation of
a simple 3D model
Simple 3D model of Todaiji temple's
'Seated Statue of Miroku'

(5)The contour-line plans can be used to create section-outline templates to check
  the shape during the sculpting process.

Section-outline templates based
on the contour-line plans
View of the section-outline templates being used
to create a reproduction sculpture

As can be seen from the descriptions above, 3D digital data can be used to facilitate every stage of the work from the timber cutting and dividing, through the rough carving and mid-finish, allowing it to be carried out speedily and without hesitation.
However, when creating a reproduction of a cultural property, it is impossible to grasp the texture, size and other factors that give the work presence solely from the data and in this context, it can be said that 3D digital data alone is insufficient. 3D digital data needs to be combined with the eye and skill of an accomplished sculptor in order to capture the spirituality of the original.
In the future, we can look forward to technical advances in laser scanners and software and so it is necessary for further research be made into the possibilities of utilizing this in the creation of reproduction statuary.
Reproduction of Todaiji temple's 'Seated Statue of
Miroku' (by KOBAYASHI Kyoko)
Reproduction of Kofukuji temple's 'Ryutoki'
statue (by MASUDA Yoshiki)
Acknowledgment This work was supported by KAKENHI(17300288), FOUDATION FOR CULTURAL HERITAGE AND ART RESEARCH and donation from Prof. Satoshi YABUUCHI
3D Images: A project carried out in collaboration between the Conservation and Restoration: Sculpture,
Conservation Division, Graduate School of Fine Arts, Tokyo National University of Fine Arts and Music and
CAD Center Corporation.