Restoring the Lions' Roar: Documenting and Replicating Limestone Sculptures through Laser Scanning, 3D Modeling, & CNC Machining Presentation
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Presentation given at the 3D Digital Documentation Summit, at the Presidio of San Francisco, in San Francisco, CA on July 11, 2012.
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Restoring the Lions' Roar: Documenting and Replicating Limestone Sculptures through Laser Scanning, 3D Modeling, & CNC Machining Presentation
- 1. R E S T O R I N G T H E L I O N S ’ R OA R : D O C U M E N T I N G A N D R E P L I C AT I N G L I M E S T O N E S CULPTURES THROUGH L ASER S CANNING, 3 D M ODELING, & C N C M ACHINING C A I T L I N S M I T H | C O N S E R VAT O R | K R E I L I C K C O N S E R VAT I O N , L L C 3 D D I G I TA L D O C U M E N TAT I O N S U M M I T | J U LY 2 0 1 2 | S A N F R A N C I S C O
- 2. AUTHORS: CAITLIN SMITH, PROJECT CONSERVATOR, KREILICK CONSERVATION, LLC T. SCOTT KREILICK, PRESIDENT/CEO/PRINCIPAL CONSERVATOR, KREILICK CONSERVATION, LLC HARRY ABRAMSON, PROJECT MANAGER, DIRECT DIMENSIONS, INC. , , , GLENN WOODBURN, TECHNICAL PROJECT MANAGER, DIRECT DIMENSIONS, INC. JON LASH, PRESIDENT/CEO, DIGITAL ATELIER, LLC 3 D D I G I TA L D O C U M E N TAT I O N S U M M I T | J U LY 2 0 1 2 | S A N F R A N C I S C O
- 3. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 “Presented to the citizens of Essex County by the Prudential “P t d t th iti fE C t b th P d ti l ntroduction Insurance Company of America, from 1892 to 1958, more than half a century, this lion, with its twin companion, sculptured by Karl Bitter, stood guard over the doorway of the First Prudential Building in Newark at 763 Broad Street, g In corner of Bank Street. They have witnessed the growth of Newark from a town to a metropolis.” Laser Scans S Karl Bitter,. Karl Theodore Francis Bitter papers, Archives of American Art, Smithsonian Institution. Machining Conclusions Prudential
- 4. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In The New York Times Laser Scans S Pantel del Cueto & Associates Machining Conclusions Pat
- 5. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In The New York Times Laser Scans S Pantel del Cueto & Associates Machining Conclusions
- 6. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction CLIENT GOALS: OPTIONS: Preserve original fabric 1. Maintain originals P Promotional visibility ti l i ibilit 2. Make 2 M k molds off originals ld ff i i l In Public accessibility 3. Laser scan & create Laser Scans digital models Documentation S TIMING IS EVERYTHING: Machining 1. Before de-installation – in case of catastrophic failure 2. After cleaning, before physical alteration – model replacement elements electronically p y 3. After conservation & reconstruction – wait until end of restoration process Conclusions 4 After cleaning & clay reconstruction, before permanent repairs – 4. reconstruction scanning occurs sooner, enlist the skills of a sculptor
- 7. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In Laser Scans S Machining Conclusions
- 8. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In Laser Scans S Machining Conclusions Surphaser® 25HSX
- 9. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In Laser Scans S Machining Conclusions
- 10. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In Laser Scans S Machining Conclusions
- 11. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In Laser Scans S Machining Conclusions
- 12. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In Laser Scans S Machining Conclusions
- 13. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 BENEFITS DISADVANTAGES ntroduction Physical storage – Costs of technology Long-term storage – Costs of accuracy In Relative ease of manipulation – Changes in technology Accuracy – File size & storage Laser Scans Protection of original fabric – Loss of detail in replicas S Protection of new repairs – Not exact replicas Machining Conclusions
- 14. R ESTORING THE L IONS’ R OAR: D OCUMENTING |CAITLIN SMITH |KREILICK CONSERVATION, LLC AND R EPLICATING L IMESTONE S CULPTURES |JULY 2012 ntroduction In Laser Scans S Machining Conclusions
- 15. Q UESTIONS & C OMMENTS ? P L E A S E C O N TAC T CAITLIN SMITH C O N S E RVAT O R K R E I L I C K C O N S E RVAT I O N , L L C 5 1 9 T O L L R OA D, O R E L A N D, PA 1 9 0 7 5 C S M I T H @ K R E I L I C KC O N S E RVAT I O N . C O M K R E I L I C KC O N S E RVAT I O N . C O M 3 D D I G I TA L D O C U M E N TAT I O N S U M M I T | J U LY 2 0 1 2 | S A N F R A N C I S C O
Editor's Notes
- Good morning. My name is Caitlin Smith, I am a conservator with Kreilick Conservation, and my talk today is “Restoring the Lions’ Roar: Documenting and Replicating Limestone Sculptures through Laser Scanning, 3D Modeling, & CNC Machining.” This presentation details the collaboration between Kreilick Conservation, Direct Dimensions, & Digital Atelier. It will touch on the topics of data acquisition through 3-D laser scanning, data management issues such as storage, and data applications such as 3-D modeling and physical reconstruction.
- The authors of this presentation are: Caitlin Smith, Project Conservator, Kreilick Conservation, LLC T. Scott Kreilick, President/CEO/Principal Conservator, Kreilick Conservation, LLC Harry Abramson, Project Manager, Direct Dimensions, Inc. Glenn Woodburn, Technical Project Manager, Direct Dimensions, Inc. Jon Lash, President, Digital Atelier, LLC
- INTRODUCTION In January 2011, Kreilick Conservation was engaged by Beaver Electric Co. to conserve the Branch Brook Park Prudential Lions . The Prudential Lions , were sculpted by Karl Bitter (1867-1915). Karl Bitter was born in Vienna, Austria and immigrated to New York City in 1889. Bitter worked on a number of notable public sculpture projects for major architects, including Richard Morris Hunt and George B. Post. His private commissions went to a number of large residences, including the Vanderbilts, Astors, and Rockefellers. Some of his most famous pieces are the bronze gates of Trinity Church in Manhattan, ornament for Hunt’s Administration Building at the 1893 World’s Columbian Exposition in Chicago, the decoration for Post’s Wisconsin State Capitol, the Pomona fountain in front of New York’s Plaza Hotel. He was Director of Sculpture at the Buffalo Pan-American exposition, the St. Louis World’s Fair, the Panama-Pacific Exposition, and President of the National Sculpture Society. The Prudential Lions were installed over the doorway of the Prudential Insurance Company, in Newark, New Jersey, in 1901. They were inspired by the lion on the company’s 20 year locket, meant to signify both strength and being on guard. After the building was demolished, the Lions were installed in Branch Brook Park, Newark, New Jersey in 1959. The quote you are seeing comes from the plaques presented upon their installation, it notes that for “more than half a century, this lion, with its twin companion... stood guard over the doorway of the First Prudential Building... They have witnessed the growth of Newark from a town to a metropolis.” They spent another half century in Branch Brook Park, where they became mascots for the park and the Park Alliance. Children played on them, vandals painted them. In 2011, the Park Alliance began a facelift of the Music Court where the Lions sit.
- The Prudential Lions are carved limestone companion sculptures depicting seated male lions, each with a front paw resting on a sphere. The Lions are approximately seven feet tall and weigh 2,900 pounds each. Before treatment, the limestone sculptures exhibited staining, biological growth, gypsum crusts, graffiti, mechanical damage, spalling, and erosion of details. The Lions were missing portions of their tails, teeth, claws, and snouts. On top of all of this, a series of painting campaigns were undertaken to cover these conditions.
- This project began as a restoration/conservation effort. Treatments such as water-misting, paint removal, salt poulticing, laser cleaning, and Dutchman were undertaken. Then in August 2011, after conservation work had begun on the sculptures, the project was expanded to include the creation of full-scale Lion replicas. The shift came from a desire to preserve the original statues for the future. The client wanted to take advantage of their high visibility for promotional purposes, keep them accessible to the public, while also keeping an accurate representation of their forms for the future. With these considerations in mind, we presented the client with several options. Firstly, to do nothing beyond restoring and maintaining the originals. Secondly, to make molds off of the restored sculptures. Thirdly, to laser scan the sculptures and create digital models from which replicas and molds could be created. Laser scanning and 3D modeling were eventually selected as the best option. In the past, these sculptures were subject to vandalism and wear and tear from park visitors. Some sort of documentation was desirable in anticipation of their continued use in a public space. Creating molds from the original statues would have had similar results to 3D modeling, however there were concerns about the storage and shelf life of large rubber molds, and the effect the mold-making process would have on the porous limestone and new repairs. In contrast, laser scanning could be done in a single day, in place, and without touching the stone surfaces. 3D modeling from the scans could provide a digital record accurate enough to negate the need for molds, while also giving the clients the opportunity to easily create replicas/miniatures from various materials, at various sizes, for preservation and/or promotional purposes. In fact, it was this capability that allowed the Alliance to go one step further, to go ahead and relocate the original sculptures to a safer location, and to place replicas back in the park. To complete this work, Kreilick Conservation put together a team of 3D documentation professionals, including Direct Dimensions, Inc., who undertook the laser scanning and 3D computer modeling, and the Digital Atelier, LLC, who used the models for CNC machining foam. These foam forms were ultimately used to create molds for the precast concrete replicas.
- CONCLUSIONS What does this project represent? It demonstrates a case in which 3D digital documentation provides the best and most appropriate option for a conservation project. The advantages proved greater than those for more traditional methods of documentation, including 2-dimensional drawings, photographic documentation, and mold-making. THE BENEFITS INCLUDE: Physical storage - This eliminates the need to store large rubber molds in a controlled environment. Long-term storage – The files are stored digitally. Relative ease of manipulation - In future, the files can be manipulated to make changes to the models, to make enlargements or miniatures, and to make castings in a variety of materials (i.e. bronze, aluminum, cast stone, glass fiber-reinforced concrete (GFRC), fiberglass resin, etc.). Accuracy Protection of original fabric – The porous, weathered limestone. Protection of new repairs – Jahn repairs and limestone Dutchmen. DISADVANTAGES Costs of technology – May be comparable between mold storage and digital file/foam creation. Costs of accuracy – Choice of accuracy determined the degree of artistic finishing, but increased accuracy requires increased expenses, so there is a trade-off in paying for accuracy and paying for the involvement of an artist. Changes in technology – Must keep files up to date with the technology to read them, and/or have access to the necessary technology. File size and storage – Large files for client Loss of detail in replicas - One drawback to the scanning, machining, and reworking process was that the surface texture and eroded beddings planes of the limestone originals were minimized in the final products. In each stage, some degree of surface detail was lost, giving the foam figures and precast concrete replicas a smoother appearance. In this case, however, the client was willing to accept some degree of difference, since the replicas are recreations of the original forms, rather than exact replicas of the statues in their current state.
- LASER SCANNING Initially, the client was offered four options for the timing of the laser scanning: The first option would be to scan the lions before they were moved in the event of a catastrophic failure during the de-installation. The second time would be that point at which cleaning and paint stripping was completed, and before physical alteration had begun. In this way, replacement elements (i.e. tails, ears, teeth, etc.) could be modeled electronically before they were sculpted in new limestone or shaped with Jahn Restoration Mortar. In these scans the sculptures would appear in their aged/weathered condition, providing a record of intact historic fabric. We used this method when working on the General George McClellan Monument in Washington, DC, when a missing escutcheon was recreated using an existing escutcheon as a starting point for digital manipulation. The third time would have been after the lions had been conserved and reconstructed elements had been installed, and deteriorated features and details had been modeled in clay. This scanning would be an alternative to making rubber molds for future replication of the lions. In these scans the sculptures would be restored recreations of the Lions in 1901, interpretations made by the sculptor from historic images and client input. This would have to occur at the end of the restoration process. The option that was ultimately chosen. Scanning of the lions after cleaning and reconstruction of lost elements in clay, but before permanent repairs were made. For our client, this had two benefits. 1) This allowed for scanning to occur sooner. This meant that work on the STL files, machining of the foam, and creation of precast concrete replicas could occur at the same time Jahn repairs and stone Dutchmen were being installed on the original sculptures. 2) The client wanted to enlist the skills of a sculptor, and to be able to physically view/experience the repairs, to have editorial control over their appearance, before scanning and permanent repairs occurred. Before scanning by Direct Dimensions, Inc., conservators worked with a sculptor to restore lost details on the Prudential Lions in clay. Portions of the manes, ears, eyebrows, snouts, teeth, chin, and claws were recreated. The clay repairs were done by conservators and sculptor Pavel Efremoff. The work was based on photographic documentation from the New Jersey Historical Society, the Newark Public Library, and Prudential. The recreated elements were made available to the owner’s representatives for inspection and approval. Adjustments were made from their commentary. When the final clay models were approved, laser scanning and Jahn repairs could begin.
- After restoring lost details on the Prudential Lions in clay, Direct Dimensions, Inc. came to the conservation studio to laser scan the statues. A Surphaser® 25HSX, a phase shift, hemispherical 3D scanner, was utilized. This scanner has a 360° x 270° field-of-view and scan rate of up to 800,000 points per second. The scanner creates 3-dimensional electronic images that are accurate up to 1mm or better. This scanner collects point data to create polygonal computer models (STL files). These files were edited by the Direct Dimensions technician to ensure accuracy and to fix any gaps in the data. Scanning the statues after clay repairs allowed work on the 3D and foam models to continue simultaneously with conservation work on the original statues, including Jahn mortar repairs, stone Dutchman, and consolidation. In contrast, mold-making would have had to have occurred either on the un-restored stone surfaces, meaning any replicas would not reflect the statues’ restored appearances, or on newly patched and repaired stone surfaces, which would be vulnerable to damage during the mold-making process.
- CNC MACHINING After laser scanning, the finished STL files were given to the Digital Atelier in Mercerville, NJ. There a five-axis CNC (digitally automated via computer numerical control) machine was used to mill full-scale foam replicas in 6 lb. urethane foam. Kreilick Conservation worked with the Digital Atelier on the construction of the foam forms and the finishing of their surfaces. Each of the Lions were created in eleven separate pieces of foam. After the pieces were glued together, the surfaces required reworking. As excellent as the technology is, there is still a need for artistic involvement. The bits used to cut the hard foam aren’t able to cut any deeper than they are wide, so recesses and overhangs were not as deep as in the original sculptures. In addition, even the smallest bits used by the mechanical cutting machine leave a regular groove pattern across the surface that needed to be carved back and minimized. As such, conservators and a sculptor worked with the Digital Atelier staff to rework the entire surface of each lion and to redefine the recesses, while referencing historic photos and restoration photos.
- The finished foam figures were used by Metropole, Inc. to create molds for casting replicas. In this way, new precast concrete statues were created without endangering the original limestone figures at any point in the process.
- CONCLUSIONS The results of our labors. We went from two severely aged limestone statues, to a pride of four fierce lions.
- Here are Art and Pat, the precast concrete replicas, at home in Branch Brook Park.
- CONCLUSIONS What does this project represent? It demonstrates a case in which 3D digital documentation provides the best and most appropriate option for a conservation project. The advantages proved greater than those for more traditional methods of documentation, including 2-dimensional drawings, photographic documentation, and mold-making. THE BENEFITS INCLUDE: Physical storage - This eliminates the need to store large rubber molds in a controlled environment. Long-term storage – The files are stored digitally. Relative ease of manipulation - In future, the files can be manipulated to make changes to the models, to make enlargements or miniatures, and to make castings in a variety of materials (i.e. bronze, aluminum, cast stone, glass fiber-reinforced concrete (GFRC), fiberglass resin, etc.). Accuracy Protection of original fabric – The porous, weathered limestone. Protection of new repairs – Jahn repairs and limestone Dutchmen. DISADVANTAGES Costs of technology – May be comparable between mold storage and digital file/foam creation. Costs of accuracy – Choice of accuracy determined the degree of artistic finishing, but increased accuracy requires increased expenses, so there is a trade-off in paying for accuracy and paying for the involvement of an artist. Changes in technology – Must keep files up to date with the technology to read them, and/or have access to the necessary technology. File size and storage – Large files for client Loss of detail in replicas - One drawback to the scanning, machining, and reworking process was that the surface texture and eroded beddings planes of the limestone originals were minimized in the final products. In each stage, some degree of surface detail was lost, giving the foam figures and precast concrete replicas a smoother appearance. In this case, however, the client was willing to accept some degree of difference, since the replicas are recreations of the original forms, rather than exact replicas of the statues in their current state.
- CONCLUSIONS What does this project represent? It demonstrates a case in which 3D digital documentation provides the best and most appropriate option for a conservation project. The advantages proved greater than those for more traditional methods of documentation, including 2-dimensional drawings, photographic documentation, and mold-making. THE BENEFITS INCLUDE: Physical storage - This eliminates the need to store large rubber molds in a controlled environment. Long-term storage – The files are stored digitally. Relative ease of manipulation - In future, the files can be manipulated to make changes to the models, to make enlargements or miniatures, and to make castings in a variety of materials (i.e. bronze, aluminum, cast stone, glass fiber-reinforced concrete (GFRC), fiberglass resin, etc.). Accuracy Protection of original fabric – The porous, weathered limestone. Protection of new repairs – Jahn repairs and limestone Dutchmen. DISADVANTAGES Costs of technology – May be comparable between mold storage and digital file/foam creation. Costs of accuracy – Choice of accuracy determined the degree of artistic finishing, but increased accuracy requires increased expenses, so there is a trade-off in paying for accuracy and paying for the involvement of an artist. Changes in technology – Must keep files up to date with the technology to read them, and/or have access to the necessary technology. File size and storage – Large files for client Loss of detail in replicas - One drawback to the scanning, machining, and reworking process was that the surface texture and eroded beddings planes of the limestone originals were minimized in the final products. In each stage, some degree of surface detail was lost, giving the foam figures and precast concrete replicas a smoother appearance. In this case, however, the client was willing to accept some degree of difference, since the replicas are recreations of the original forms, rather than exact replicas of the statues in their current state.