GB2441349A

GB2441349A - A method for the scanning and preparation of a 3D object

Info

Publication number: GB2441349A
Application number: GB0617277A
Authority: GB
Inventors: Martin Woolner; Samantha Spake
Original assignee: Plymouth University
Current assignee: Plymouth University
Priority date: 2006-09-04
Filing date: 2006-09-04
Publication date: 2008-03-05
Anticipated expiration: 2026-09-04
Also published as: EP2077950A2; WO2008029116A2; GB2441349B; GB0617277D0; WO2008029116A3

Abstract

A method for the preparation of a 3D object (for example a sculpture) comprises the steps of, scanning at least a portion of the object to prepare an image data set 102, 104; modifying the image data set; and preparing a completed sculpture using the modified image data set 112, 118. The method preferably comprises the steps of, assessing an object to be sculpted 100 and identifying portions of the object with a level of detail greater than a predetermined threshold; scanning the object with the exception of the portions identified to have detail above the predetermined threshold to provide an image data set; modifying the image data set 112 to include data for the omitted portions, to provide a complete image data set for the object; and preparing a completed sculpture using the modified data set. In an alternative method, the sculpture is prepared by the steps of scanning a portion of an object to provide an image data set; preparing a partial sculpture of the scanned portion of the object using the image data set using a first technique; and preparing a full sculpted object using a second technique.

Description

METHOD FOR SCULPTING

The present invention is directed to a method for preparing a three-dimensional replica of a subject or object, in particular a method for producing three dimensional sculptures.

Traditionally, three dimensional sculptures of objects, such as human heads * 10 and animals have been prepared by hand, making the process of obtaining such a sculpture very time consuming and, as with many hand made items, extremely expensive. The traditional techniques involve preparing a replica of the object being sculpted, for example from clay or the like. The replica is typically hand made, requiring a high degree of skill and a significant length of time. Once completed, the replica may be finished, for example in the case of clay by firing, to prepare the completed work. Alternatively, the replica is used I...

to prepare a mould, from which a final work is cast.

A very well known technique for preparing the final work is by means of the lost wax casting process. In this procedure, a wax replica is prepared and then encased in a mould. The mould is heated to remove all traces of the wax and leave a cavity. Molten metal is poured into the mould to fill the cavity left by the wax. The mould is then removed to reveal the finished article in a rough cast form. The article is then finished using suitable techniques.

Accordingly, there is a need for a quicker, cheaper method of producing such sculptures, suited towards a more general market. It would also be an advantage if the method could provide accurate sculptures without the need for the high level of skill and experience required to employ the traditional techniques.

GB 2 377 506 discloses an apparatus for reproducing a human head in three-dimensional form. The replica is prepared by removing material from an oversize blank of thermoplastic material using a data set of coordinates of the surface of the subject's head.

US 5,736,201 is concerned with a process for making a replica of the head of a subject in the form of a doll's head. The process comprises scanning the head of the subject with both a laser scanner and a video camera, to produce data signals containing contour information and colour information. The * 10 countour signals are used to prepare a three-dimensional replica of the subject, after which the colour signals are used to colour the replica. * . a

CN 1105035 C discloses a method for manufacturing three-dimensional metal statues. The method comprises scanning the subject to obtain data on the shape and configuration of the subject. The data thus obtained are input into a computer, which is then used to prepare an epoxy resin model. A silicone *..

elastomer mould is prepared from the resin model, which is in turn used to prepared a wax model. The wax model is used in a lost wax casting process to prepare the final cast metal replica.

While the aforementioned methods and procedures assist in reducing the need for a skilled artist or sculptor to create a replica of a subject, the prior art methods do not allow for the fast and accurate replication of a subject using modern imaging and three-dimensional modelling techniques. In particular, it would be most useful if a method could be found to enable modern rapid-prototyping systems to be employed to produce either the final replica or the replica used in a casting process, such as the traditional lost wax casting techniques.

According to the present invention, there is provided in a first aspect a method for the preparation of sculpted objects, the method comprising the steps: (a) scanning at least a portion of the object to be sculpted to prepare an image data set; (b) modifying the image data set; and (c) preparing a completed sculpture using the modified image data set The method of the present invention employs scanning technology to provide an image data set of the object to be reproduced. This ensures that the reproduction is accurate. In addition, the data set is modified as required, as described hereinafter, in order to produce the completed sculpture. As will be described, the method may be used to prepare a range of reproductions or sculptured objects, in particular statues of people and/or animals, busts and * S *** cameos. S. * SS

The method may employ any suitable scanning technique in order to obtain an image data set of the object being reproduced. The image data set will :.::. contain data of the object in three dimensions, in turn allowing a three-8.*S dimensional reproduction to be produced. Accordingly, the scanning technique employed must be one that provides a three-dimensional data set.

Suitable scanning techniques are known in the art and suitable scanning systems are commercially available. Preferred scanning systems include 3D non-contact laser scanners/digitisers, for example the Konica Minolta Vi910, commercially available from Konica Minolta Sensing Europe B.V.

The scanning step is conducted to obtain an image data set of at least a portion of the object being sculpted and, in some embodiments, a complete image data set. To enable the mapping of a complete three dimensional image, the object is preferably scanned a plurality of times, in particular at least three times, more preferably at least six times and the image data set compiled from the data obtained from each scan. Each scan will typically last from 1 to 5 seconds, more particularly about 2.5 seconds.

The scanning step of the method may be carried out to generate an image data set for the entire object. In this respect, the reference to the image data set being for the entire object is to be taken to mean all the image data necessary to prepare the desired sculpture. In some cases, for example in the case of a sculpture of a person's head or bust or a complete person or animal, the image data will be of the entire object. However, in other cases, for example in the preparation of a cameo, it is necessary only to obtain image data of a part of the object or subject. Alternatively, the data set may be obtained for just a portion of the object required in order to prepare the : ** 10 desired sculpture. The reasons for this are as follows. S... * S S...

It has been found that current three dimensional scanners used in the art are *...

: of such high resolution and quality that the image data set produced contains too much detail of the image for the efficient and successful completion of the * 15 further steps of the process. In particular, it has been found that subjects with hair and fur, such as heads of people and animals, are imaged with such accuracy by current scanning systems that a very large number of bits of data are required in order to represent the object at such high resolution. The resultant large number of data renders the image data set difficult and slow to manipulate. In addition, it has been found the procedures for preparing the completed sculpture using the image data set cannot operate sufficiently with such a high image resolution.

CN 1105035 C discussed hereinbefore discloses that the sensitivity of the scanning system may be adjustable. While this is one approach to overcoming the aforementioned problem, it has been found difficult to adjust the resolution of the imaging system to compliment precisely the systems used in the later steps in the method, while at the same time maintaining the overall accuracy of the reproduction. In addition, and perhaps more importantly, it has been found most advantageous to be able to scan the object at the highest resolution possible and to amend or modify the resulting image data set. In this way, the image data set obtained from the scanning step is of the highest quality. The resolution of the entire image data set or just significant portions may be adjusted according to the nature of the subsequent sculpting procedures. Further, manual or automatic manipulation of the image data set is improved when working with the high resolution data and produces improved results.

If the object is to only have a portion of its surface scanned, it is preferable to assess the object before the scanning stage, in order to determine the nature : *. 10 of the features of the object and the detail thereof. The portions of the object I...

having a level of detail above a predetermined threshold, such as the hair and fur of subjects, may be omitted from the scan. The remaining portions of the object, having surface details that do not exceed the threshold, are then scanned to produce the image data set. * *

:.. Thus, for example, in the case of a completed sculpture being prepared from **** an image data set using rapid prototyping (RP) techniques, as in one particularly preferred embodiment of the present invention, the threshold value of the level of detail to be tolerated is set by the RP system, in particular the resolution to which the system can operate, the materials being used and the length of time to be taken in preparing a reproduction from the image data set.

In general, the higher the resolution of the image data set, that is the higher the level of detail, the longer the RP system will take in translating the image data into an object. In one case, therefore, the detail threshold will be set by the length of time to allocated to the RP system for prepartng the replica.

Thus, the present invention in this embodiment, elects to have the scanning system operate at its highest resolution and omit those features that have too much detail for subsequent sculpting using the image data set. Portions of the object surface have a sufficiently low amount of detail, for example a face, clothing or the like, are imaged at the high resolution to provide a partial image data set of the object. It will thus be appreciated that the present invention defines the portions of the object to be scanned by the nature of the surface features, rather than by adjusting the sensitivity or resolution of the

scanner, as is relied upon in the prior art.

In embodiments of the method in which just a portion of the object is scanned, the resulting partial image data set is modified to include image data for the omitted portions of the object. Software available to manipulate and modify an image data set in this manner is well known and commercially available in : *. 10 the art and includes various computer aided design (CAD) packages and reverse engineering software packages, which allow a user to add features to an image. Examples of suitable commercially available software packages include GeomagicTM, commercially available from Interplex Ltd., and Magics RPTM, commercially available from Materialise N.V. In this way, the omitted * 15 portions of the image data set may be added by hand or automatically, in order to create a modified image data set of the entire object to be **.* reproduced.

In an alternative embodiment of this aspect of the present invention, the entire surface of the object to be sculpted is scanned and an image date set of the complete object obtained. Again, this will be carried out using the scanner at a high level of resolution, that is to capture a high level of detail. The image data set is then modified to identify those portions of the image data set that exceed a threshold detail level determined by the subsequent processes to be undertaken. The image data set is then modified to bring the detail level of the entire image to below the threshold value. Software available to manipulate and modify an image data set in this manner is well known and commercially available in the art and includes various CAD packages and reverse engineering software packages, as aforementioned, which allow a user to modify features in an image. In this way, the level of detail of the image data set may be altered by hand or automatically, in order to create a modified image data set of the entire object to be reproduced.

Again, the image data set is adjusted according to a threshold for detail that is determined by the subsequent processing techniques to be employed, such as RP, as described hereinbefore.

Further operations or manipulations of the data in the image data set may be carried out in the preparation of the image data set. For example, the image * *. 10 data may be altered to remove unwanted features or alter features according to the sculptor's or subject's wishes. For example, blemishes and marks on a person's skin may be removed, as desired. In addition, the scale of the image data may be adjusted, in particular to increase or decrease the scale of the * object to be prepared from the image data set. In many cases, for example in * 15 the case of the sculpting of an animal or person, in particular a full figure or a bust, the finished sculpture will be required to be considerably smaller than **** life-size. This will reduce both the size and weight of the completed sculpture, for example, a replica at half scale having only one eighth the volume and material of the full-size object.

The image data set may be modified to change the ratio of the sizes of the image in each dimension. In one embodiment, the image data set is modified to reduce the scale of the image in one dimension. Thus, in the case of an image having axes x, y and z, the image data set may be modified to reduce the image along the z axis, while retaining the size of the image in both the x and y axes. In this way, a modified image data set may be prepared that can be used to prepare a replica in the form of a medal, medallion, plaque or cameo. Surprisingly, it has been found that the image data file may be modified in this way without introducing major distortions to the overall image and the final appearance of the replica. By way of example, the image data set may be modified to adjust the scale of the image in one dimension or along one axis by a factor of from 0.1 to 0.5, for example 0.25, without the final replica being distorted.

The modified image data set is used in the subsequent processing, which creates a replica and finished sculpture according to the modified data set.

This may be achieved in a variety of ways.

In one embodiment, the modified image data set is used in the direct preparation of the final sculptured object. For example, the modified image * ** 10 data set may used as the input to a computer controlled milling machine, lathe or the like. In one particularly preferred embodiment, the modified image data set is input into a rapid prototyping (RP) system. Rapid prototyping is a modern technique, by which objects are constructed using the successive deposition of material in a solid freeform fabrication (often referred to as three-dimensional printing) according to a set of computer generated instructions.

:,::.. The RP system deposits liquid or powdered material in successive layers in ***e accordance with a set of profiles or contours communicated to it, in order to construct the completed article. Suitable RP systems are known in the art and are commercially available. Examples of RP systems and techniques include stereolithography apparatus (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), laminated object manufacturing (LOM), inkjet systems and three dimensional printing (3DP) The RP systems may be used to prepare or construct a reproduction using any suitable material, most specifically plastics, ceramics and metals.

Suitable plastics include acrylonitrile butadiene styrenes (ABS), polycarbonates and polyphenyl sulphones. The RP system may be employed to deposit a single material to construct the reproduction. Alternatively, two or more materials may be used. In one embodiment, a two-component system is used, in which one component has a low melting point or is soluble in a suitable solvent and such component may be removed by suitable heating or dissolving in a solvent. In this way, a reproduction may be prepared that is hollow, for example to reduce overall weight of the sculpture.

Suitable conversion of the modified image data file to a format readable by the RP system may be required. For example, many CAD and reverse engineering software systems are operable to output data files in STL format, which acts as an interface between a CAD system and an RP system. Other suitable conversions and interfaces will be known to the person skilled in the art.

: .. 10 A particularly preferred embodiment in which the image data set is used directly in the preparation of the finished sculpture is in the preparation of a cameo. In this embodiment, the image data set is used directly in a process, such as milling or rapid prototyping to prepare a cameo. It has been found that cameos of a very high quality comparable to those prepared using :.::.. conventional and traditional techniques may be prepared quickly and cheaply, S...

by persons with little or no skill in the art of cameo making.

As noted, the image data set may be employed directly in the preparation of the completed sculpture, for example using the various RP techniques discussed hereinbefore. In an alternative embodiment, the image data set is used to prepare a replica of the object being sculpted. Such a replica may be prepared using the aforementioned techniques, in particular RP. The replica is then used in a further process to prepare the completed sculpture. Suitable processes include vacuum forming and casting. Casting is a particularly preferred technique for preparing the completed sculpture.

In one embodiment, the replica, for example prepared using RP, is employed in a conventional lost wax casting process, in which the replica is used to prepare a wax replica, which is used in turn in the lost wax casting in known manner. Alternatively, the replica prepared directly from the image data, in particular using RP techniques, is employed directly in an analogous process, in which the replica is prepared from a low-melting point plastic, such as ABS, and replaces the wax replica in the lost wax process. Such a process is referred to herein as a lost material casting process'.

As an alternative, the replica prepared directly from the image data set may be used as the form in a vacuum moulding process, in which the completed sculpture is prepared by vacuum forming a suitable material over the replica.

Suitable vacuum forming techniques will be known to the person skilled in the : * 10 art.

In still a further embodiment, the replica prepared from the image data set is used to prepare a die for the preparation of a medal or medallion or the like by :. striking. In the striking process, a die is prepared from a suitable material to have a negative impression of the final desired form. A blank medal, medallion or the like is then struck using the die, to leave the final form. The replica produced in the present invention may be used, in turn to prepare a die. Alternatively, the replica may be prepared having a negative form and used directly as a die itself. Suitable systems and techniques for forming a die for striking a medal or medallion are known in the art and commercially available. One suitable technique to prepare the die is computer aided milling.

In a further aspect, the present invention provides a method for the preparation of sculpted objects, the method comprising the following steps: (a) inspecting an object to be sculpted and identifying portions of the object with a level of detail greater than a predetermined threshold; (b) scanning the object with the exception of the portions identified in step (a) to have detail above the predetermined threshold to provide an image data set; (C) modifying the image data set to include data for the omitted portions, to provide a complete image data set for the object; and (d) preparing a completed sculpture using the modified data set.

A still further aspect of the present invention provides a method for the preparation of sculpted objects, the method comprising the following steps: (a) scanning an object to provide an image data set; (b) assessing the image data set to identify portions of the image data having a level of detail above a predetermined threshold value; * * 10 (C) modifying the image data set to reduce the level of detail to below the predetermined threshold value and *** (d) preparing a completed sculpture using the modified data set. I... * * * ** I

The features and techniques of the steps in the methods of the : * 15 aforementioned two aspects of the invention are as hereinbefore described. S... S...

In a further aspect, the present invention provides an image data set prepared as hereinbefore described, which is intended for use in the preparation of a completed sculpture, again as hereinbefore described. Accordingly, there is provided in this aspect, a method for preparing an image data set for use in the preparation of a sculpture of an object, the method comprising the steps of (a) scanning at least a portion of the object to be sculpted to prepare an image data set; and (b) modifying the image data set to provide a modified image data set in a form suitable for use in the preparation of a sculpture of the object.

The scanning of the object and modification of the resulting image data set are as set out and described above.

In the methods of the various aspects of the invention set out above, the problem of the image data set have a level of detail or resolution exceeding that which is practicable or feasible to employ in the subsequent steps to prepare the replica and/or completed sculpture is overcome either by scanning only a portion of the object and completing the image data set by some other means or by scanning the entire object and modifying the image data set accordingly. As an alternative to these embodiments, it has been found that the problem may be overcome by preparing only a partial image data set of the object, using the partial image data set to prepare a particular partial sculpture of the object and completing the sculpture using another sculpting technique. Accordingly, in a further aspect of the present invention, * * 10 there is provided a method for the preparation of a sculpted object, the method comprising the following steps: (a) scanning a portion of an object to provide an image data set; (b) preparing a partial sculpture of the scanned portion of the object using the image data set using a first technique; and : * 15 (c) preparing a full sculpted object using a second technique. S...

In the method of this aspect of the present invention, the object is scanned.

Suitable scanning systems and techniques are as set out above. The object to be sculpted is scanned only in those portions that have a level of detail that is below a predetermined threshold and allows the image data thus generated to be utilised in subsequent first sculpting processes. Preferably, the method comprising the step of assessing the object prior to being scanned, in order to identify the level of detail of the different portions of the object. The portion scanned is then the portion selected to have a level of detail within the working range of resolution of the subsequent first sculpting technique.

The image data set may be modified prior to being used in the preparation of the partial sculpture, for example to correct or alter features of the image, or to adjust the scale of the image, as described hereinbefore. Suitable software packages for the manipulation of the image data, such as CAD packages and reverse engineering software packages, are well known in the art, as mentioned hereinbefore.

The image data set, whether generated directly by the scanning step or modified, is used by a first sculpting technique to prepare a partial replica of the object. Suitable first sculpting techniques include milling and the various rapid prototyping systems described hereinbefore. The operation of such techniques are dependent upon the detail level in the image data.

* 10 Once the available image data have been used to prepare the partial replica, the remainder of the replica is prepared using a second sculpting technique.

The second sculpting technique may be one of the aforementioned processes or systems, such as milling or RP, but operating from a different data set, such as a standard or independently programmed data set. Other second sculpting techniques include finishing the sculpting by hand. This is particularly desirable in the preparation of cameos, which have traditionally I...

been prepared by hand.

The full sculpted object may be the completed sculpture, prepared for example by a combination of RP and hand finishing. Alternatively, the full sculpted object may be used in further processing, such as casting, in order to prepare the completed sculpture. Suitable casting processes are as hereinbefore described. A particularly preferred casting process is the lost material casting process, using the replica prepared using RP.

Embodiments of the present invention are described in relation to the production of three dimensional sculptures and cameos of human heads and animals. However, it is to be understood that the invention applies to the production of three dimensional sculptures and cameos of any number of objects.

Embodiments of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which: Figure 1 is a schematic representation of an imaging and sculpting system according to one embodiment of the present invention; and Figure 2 is a schematic representation of methods according to embodiments of the present invention.

* 10 Referring to Figure 1, there is shown an object 2 to be sculpted, in this case the head of a person. The object 2 comprises a portion 4 that has a level of detail below a threshold value, in particular the face of the subject. In addition, the object 2 has a portion 6 that contains many small features having a level of detail exceeding the threshold value, in particular the hair of the person. * . * * * **4. I...

An imaging system 8 is used to obtain several images of the object 2 and to provide an image data set. The portions of the object 2 that are scanned and imaged by the imaging system 8 are as described below with reference to Figure 2.

The image data set is supplied to a computer 10 programmed with suitable CAD software or a reverse engineering software package to modify the image data set. Again, modification of the image data set will be described below with reference to Figure 2.

The modified image data set produced by the computer 10 is fed to a rapid prototyping (RP) system 12, by way of a suitable software interface, such as SIL. The RP system 12 may be used to produce a completed sculpture 14 directly from the image data set. Alternatively, the RP system 12 may be used to prepare a replica from the image data set that is in turn used in a lost material casting process 16 to prepare the completed sculpture 18.

Methods for the preparation of a completed sculpture are represented schematically in Figure 2. Thus, in a first object assessment step 100, the object to be sculpted is analysed to determine the level of detail in the features of the object. This analysis may be carried out automatically using a suitable image analysing system. Alternatively, or in addition thereto, the assessment of the object may be by eye. * 10

Once the object assessment has been completed, the object is scanned in one of two alternative scanning steps 102 and 104. In the first alternative scanning step 102, the portion of the object having a level of detail below a predetermined threshold value is scanned. Thus, in the embodiment shown in Figure 1, the hair 6 of the subject 2 is not scanned, as the level of detail of the hair exceeds that which is workable usingthe RP system 12. * S.. * S

The partial scan 102 generates a partial image data set. In one embodiment, the partial image data set is used directly in a RP step 106 to prepare a partial sculpted object or replica, which is then finished by a hand sculpting step 108 to add the missing portions of the sculpture and provide a full replica 110. As an alternative to this, the partial image data set is first modified in a data modification step 112, before being provided to the RP step 106.

In a second embodiment, the partial image data set is subjected to a data modification step 112, in which the image data from the scan are supplemented with image data input by hand and/or automatically generated to provide a modified, full image data set. The data modification step 112 may also include other manipulations of the image data, in particular adjustment of the scale of the replica. The modified, full image data set is fed to a RP step 114, via a suitable interface, in which a full replica 116 of the object is prepared.

In the case that the object to be sculpted is subject to a full scan 104, the image data set produced is a full image data set. This data set is subjected to a data modification step 118, in which the detail level of the image data is reduced to below the threshold level. Other modifications or manipulations of the image data as hereinbefore described, may also be made in the step 118.

The modified image data set thus produced is provided, via a suitable * 10 interface, to a RP step 120, in which a full replica 122 of the object is prepared. **** * S ****

The full replicas 110, 116 and 122 produced in the three alternative method embodiments shown in Figure 2 may be the final, completed sculpture.

Alternatively, they may be employed in a casting process, in particular a lost material casting procedure, to prepare a cast completed sculpture. S...

S S S...

Applications for the process include, but are not limited to, the sculpting of human heads to provide three dimensional portraits, and providing replicas of animals, such as dogs, cats and horses.

Claims

CLAIMS

1. A method for the preparation of sculpted objects, the method comprising the steps: (a) scanning at least a portion of the object to be sculpted to prepare an image data set; (b) modifying the image data set; and (c) preparing a completed sculpture using the modified image data set.

2. The method according to claim 1, wherein the completed sculpture is a : ** three dimensional sculpted object. *S..

3. The method according to claim 1, wherein the completed sculpture is a :, 15 cameo or a struck item.

S

S

4. The method according to any preceding claim, further comprising the * S * * S step of assessing the object to be sculpted before scanning to 5*s.

5"... determine the degree of detail of features of the object.

5. The method according to any preceding claim, wherein the scanning is carried out to provide an image data set of only a portion of the object.

6. The method according to claim 5, wherein the image data set is modified in order to add image data for the unscanned portion of the object.

7. The method according to either of claims 5 or 6, wherein, before scanning, the object is assessed to identify those portions of the surface having detail below a predetermined threshold, the scanning being limited to those portions so identified.

8. The method according to claim 7, wherein the predetermined threshold of detail is established by the characteristics of the techniques used to form the completed sculpture in step (c).

9. The method according to any of claims 1 to 4, wherein the entire surface of the object is scanned.

10. The method according to any preceding claim, wherein the image data set is modified in step (b) to identify those portions of the image which have detail exceeding a predetermined threshold and to modify the data corresponding to those portions to bring the detail below the threshold.

* ** 11.The method according to claim 10, wherein the predetermined . threshold of detail is established by the characteristics of the II..

techniques used to form the completed sculpture in step (C). S. * .5

:. 15 12. The method according to any preceding claim, wherein preparation of : * the completed sculpture involves using rapid prototyping techniques. SI.. *I..

13. The method according to any preceding claim, wherein the completed sculpture is prepared by casting.

14. The method according to claim 13, wherein the completed sculpture is prepared using a lost material casting procedure.

15.The method according to claim 14, wherein the lost material casting procedure employs a replica prepared using rapid prototyping techniques using the modified image data set.

16. The method according to any of claims Ito 12, wherein the completed sculpture is prepared using vacuum moulding techniques or by striking using a die.

17. The method according to any preceding claim, wherein the image data set is modified to change the scale of the sculpture to be greater or smaller than the object.

18. A method for the preparation of sculpted objects, the method comprising the following steps: (a) assessing an object to be sculpted and identifying portions of the object with a level of detail greater than a predetermined threshold; (b) scanning the object with the exception of the portions identified in step (a) to have detail above the predetermined threshold to provide an image data set; (c) modifying the image data set to include data for the omitted portions, to provide a complete image data set for the object; and * * (d) preparing a completed sculpture using the modified data set. * S * *.S.

19.A method for the preparation of sculpted objects, the method *:, comprising the following steps: *5 *:. 15 (a) scanning an object to provide an image data set; : (b) assessing the image data set to identify portions of the image data having a level of detail above a predetermined threshold * S value; (C) modifying the image data set to reduce the level of detail to below the predetermined threshold value; and (d) preparing a completed sculpture using the modified data set.

20.A method for the preparation of a sculpted object, the method comprising the following steps: (a) scanning a portion of an object to provide an image data set; (b) preparing a partial sculpture of the scanned portion of the object using the image data set using a first technique; and (C) preparing a full sculpted object using a second technique.

21 The method according to claim 20, further comprising the step of assessing the object to identify the level of detail of different portions of the object, the portion of the object scanned in step (a) being that portion having a level of detail below a predetermined threshold value.

22. The method according to claim 21, wherein the threshold level of detail is determined by the first technique employed in step (b).

23. The method according to any of claims 20 to 22, wherein the first technique is rapid prototyping.

24. The method according to any of claims 20 to 23, wherein the second technique is sculpting by hand.

25.The method according to any of claims 20 to 24, wherein the image data set is modified prior to being used to prepare the partial sculpture.

: *** 26.The method according to any of claims 20 to 25, wherein the full S...

sculpted object is the completed sculpture. S...

:::: 27.The method according to claim 26, wherein the completed sculpture is * a cameo or a struck item. S..

: * 28.The method according to any of claims 20 to 25, wherein the full sculptured object is used in a casting process to prepare a completed S...

sculpture by casting.

29.The method according to claim 28, wherein the casting process is a lost material casting process.

30. A method for preparing an image data set for use in the preparation of a sculpture of an object, the method comprising the steps of: (a) scanning at least a portion of the object to be sculpted to prepare an image data set; and (b) modifying the image data set to provide a modified image data set in a form suitable for use in the preparation of a sculpture of the object.

31.A method for preparing a sculpted object substantially as hereinbefore described, having reference to either of Figures 1 or
2.

32.A method for preparing an image data set for use in the preparation of a sculpture of an object substantially as hereinbefore described having reference to either of Figures 1 or 2.

33. An image data set prepared by a method according to either of claims 300r32.

34.A sculpted article prepared by a method according to any of claims ito 31. * S. ** . *.. **.. * S

*s.s 10 55.5 * S * S. I S.. * . * . * *55*

S S...