Enlarging a Maquette

[Merlion]

I am trying to learn more about the different ways of enlarging a tall sculpture from a maquette.

Let's say I have made a maquette and give it to a foundry to enlarge, sculpt and cast into a bronze sculpture. (Depending on the job, I may or may not fly there to do the sculpting touch up).

The foundry I use is a bit vague when I asked them, partly because it is just a casual enquiry, not really preparing for a casting job.

At that time, I was with a sculpture friend who gave them a small maquette with relatively smooth curves to be enlarge 15 times. Probably for this one, they may not use the 'textbook' method of pointers on frames.

But the example I gave the foundry is to give them a maquette of a historial warrior to be enlarged 4 times to make it a life size statue.

I would appreciate knowing what are the alternative ways that foundries would do this enlarging of a figurative sculpture.

[Jamo]

I would like to hear some more in depth discussion on this topic. I am trying to get a better understanding of this as well. I have enlarged a piece to lifesize before for bronze and it was done in a relatively liberal manner. Meaning I didn't stick to the maquette rigidly. I didn't follow the pointer system of taking coordinates and translating it exactly. I felt if I had followed this, some of the distortions in the maquette would become extremely obvious. What I did was I based my enlargement measurements on the size of a 6"2 man and translated the basic proportions to polystyrene . for example if a man is 6"2 tall then his knee should be say 14 inches off the ground. with that I took all of the proportions and placements, knee, iliac crest,sternum top of head and found those. Working with the maquette I just used it as a visual reference (while sculpting)to the enlarged piece rather than making it an exact copy.I also made sure that when enlarging, the basic proportions were enlarged by the same factor. If a sculptural element in the maquette was 4 inches long at a certain spot and the multiplication factor was 2.5 It would be 10 in the enlarged piece. I made sure that I didn't vary from this when enlarging other parts of the piece. However I also ignored less important details such as say projection outward of a chest or how round a leg was. It was only adhered to concerning dimensions such as length or height and width to a certain extent. I hope this isn't confusing. Some other ways to enlarge a maquette may be to take it somewhere to be 3d scanned. Gary would be a good one to talk to about this, however it does cost $$ and I think in the end you will still have to do some of the more subtle touch ups and sculpting anyways. Using the pointer system is a good way it is time consuming but will yield a good copy of the the original piece.

[Blake]

I though that well explained Jamo thank you.
For what it is worth, I have been told that the rule of thumb was you decrease the size by framing but you should enlarge the work by recreating it as Jamo did. Measure out the figure to ensure that the proportions of the figure are correct. Jamo “adhered to the general dimensions such as length or height and width” of the maquette as you may have a better view of the overall composition of the work. Of course my reference is only to figurative.
For what it worth, so long as your having fun…..
Blake

[Merlion]

I now notice Tuck Langland's excellent 1999 book "From Clay to Bronze" gives some information on this question.

The book does not explain what are the enlargement practices of bronze foundries, but it does explain quite a few alternate methods for artists to do their own enlargement.

On the latter, he explains with illustrations six methods. They are:

The "Eyeball" method, ".. eyeball the work and then enlarge it."

The "Frame" method, "... uses a frame, with strings strung in a grid pattern."

The "Grid-up" method, "... find points in space by first finding them on a base and then going up the correct distance."

Enlarging machine, "... enlarging machines ... measure points in space. A good machine will touch a given point on the maquete and then indicate exactly whre that point should be in space on the enlargement."

The "Slice Bread" method, "... a small maquette is created in plaster, then sliced on a band saw just like a loaf of bread. Each slice is then enlarged in Styrofoam, and these slices are stacked to create the enlargement. One way to enlarge the slices is by using slides." and

The Computer-Generated Milled Foam Method. "There are firms around the country (USA) that will take your maquette and 'read' it with a laser, which then records the many points of the surface on a computer. Usually, they take something like a quarter million points off a model. Then a special three-dimensional milling machine uses those points to mill, or carve, a piece of dense rigid foam just like your maquette, only larger (or smaller)."

[George]

Here is a link to some images that explain somewhat of how an enlargement is created. This is one that I recently completed from 7 feet (1/3 scale) to 21 feet. This was a commissioned job, therefore the accuracy was of utmost importance. This job took 6 months approximately. The finished enlargement is now a bronze sculpture at the Peabody Museum of Nat Hist at Yale University.

[George]

Here is the link, forgot to paste in on last reply

www.georgemummert.com (http://www.georgemummert.com)

click on enlargement process on the first page..

[BMBourgoyne]

I've been using a combination of digital and traditional techniques for my own work-- see my page on enlargements on my website at
http://www.bourgoynestudio.com/bourgoyneSTUDIO/BMBSculpt_enlargements.html

I basically use a 3d scanner to get an accurate digital model, using 3d cad software to cross-section the model and design an armature. I then print the plans (including each cross-section, top and side views of the sculpture at full scale, and armature templates) on a plotter. Its then just a matter of cutting each cross section out of styrofoam sheets, bending the armature steel according to the templates, and fitting it all together. Clean up the surface with shapers, cover it all with aluminum foil, and its ready for the clay.

All in all, I get a proportionally accurate enlargement with major details for a low cost and in a timely manner. By using somewhat older technology (my scanner is about 5 years old) and by manually cutting each cross section rather than using CNC, I keep the costs way down. Designing the plans digitally speeds up the manual parts of the process tremendously-- all the time-consuming measuring is left to the computer and the only redundant manual task is cutting the cross-sections and gluing them up, which is very fast when done in styrofoam. Accuracy depends only on the level of care in putting it all together, as the scanner is accurate to about 0.5mm.

The level of detail that is maintained is pretty remarkable considering how basic the method is. In fact, the final shaping is pretty much a matter of following the contours, so it is almost like painting-by-number. And depending on how the armature is designed, it can be very easy to revise and refine the enlargement after-the fact, if desired.

To help pay for the scanner, I offer scanning services to other sculptors, as well as the 3d design (at a very low price). I can scan the maquette, design the enlargement, and email the plans for a very low cost. Or I would be happy to explain the process in detail if your interested being able to do it yourself. Contact digitizers and software can be affordable when compared to pointing-up manually. Email me via my website contact if you'd like to know more.

good luck with it,
Brad

[dirdim]

We provide digital enlargement services. Sounds like a perfect fit for this process.

You can bring or send us the object, or we can come to your facility. We will scan and digitially model with high precision and resolution suitable for enlargement milling, rapid prototyping, visualizations, animations, renderings, etc. We also have a great 3D web-based viewing tool that you can load on your site.


Sculpture section on website (http://www.dirdim.com/cs_sculpturearchitecture.htm), main site:
Direct Dimensions, Inc. (http://www.directdimensions.com)

[Louie Arce]

Try submerging your model in a box filled with sand. Example, if you are going to enlarge a model made of plaster and want to carve it into stone. #1 select the stone you will need for final piece. Build a wood box based on the stone around the model. Allow room for the model to be positioned in the box with room to spare. Find the area on the stone and model that is best to start carving with. Cover the model with sand and slowly remove the sand to reveal the model. make sure the box is on leval table/shake the box to level out the sand. You can allso use a grid wire system over the box to help in the scale and proportions of the carving. only carve as deep as the model potrudes from the sand...remove more sand and level ...etc untile the piece is complete

[Keropian]

I worked at a sculpture foundry in NY for ten years and worked with a 3-d pantograph machine on numerous projects for a variety of sculptors and styles of sculpture. Since I work figuratively I will explain the benefits of cnc machining and the traditional or manual 3-d pantograph machine.
At the time 80's-90's, the cnc milling and digital technology was somewhat limited to industry and just getting started in the art world, so we worked with the manual 3-d pantograph machines. Originally designed by the French in the 1700- 1800's, a good machine was accurate to a 1/16 of an inch within a 6-foot arch.
It was recommended "never" to enlarge something more than 4 times.
When you enlarge small mistakes they become much bigger mistakes!
An "accurate" large or middle size model is recommended for creating a superior enlargement. It also makes for less if any changing and cutting of the enlarged sculpture and armature; usually steel piping with foam. If the enlarged sculpture is distorted because of a faulty model it takes much more energy and more time and labor down the line to fix it. At the foundry we were always trying to be more efficient and produce a high quality enlarging for our clients.
There are certainly plus points with cnc machining sculpture to a larger size, yet there are some draw backs as well.
As you most-likely know, cnc milling is base on a digital scan of your model, it replicates the model in a urethane foam of various densities and the pieces are glued together. If an armature is needed, you can construct it by eye or use auto cad. But the foam parts must then be cut-up and placed and attached around the armature. Usually clay is then added as a skim coat to cover up the foam. By doing this you actually add additional clay to your surface. This may be okay for some sculptures, but if it is a representation figure this may not be so beneficial nor desirable.
The 3-d pantograph machine is basically two tables which turn with a chain drive. There is a ball joint on one end, on which the boom with two pointers sits, a counter balance balances the boom so there is no energy needed to hold the weight of the boom up. Once the machine is set-up, the first thing you do is weld or create the armature. The stylus on the model side traces the model as the pointer on the working end follows the trace in space. By doing this and turning the tables you can determine exactly where the armature must be placed and how big the armature must be. This takes out all the guess work. Once the armature is created foam or cardboard or in the past; wood lathing is applied to just under the working surface. This gives you freedom to apply as much or as little clay to the armature. In most cases we used 3/4" of clay, so the foam would be that distance below the finished surface. We then add the clay to slightly over the finished surface. Change the stylus to a wire loop tool, then scrape the clay as the machine traces the model.
In the end, the clay surface is exactly your finished surface not more or less.
I think when you add all the costs up for digital milling it is basically the same cost. Both methods don't capture undercuts very well, so refinement must be done by hand and eye. Again I am speaking as a figurative artist. Certainly artists of free form objects may benefit more from the digital technology while others may not. Every individual work of art has challenges and different tools to make the job easier.
I hope this helps!

Mike Keropian
http://www.keropiansculpture.com

[Keropian]

I worked at a sculpture foundry in NY for ten years and worked with a 3-d pantograph machine on numerous projects for a variety of sculptors and styles of sculpture. Since I work figuratively I will explain the benefits of cnc machining and the traditional or manual 3-d pantograph machine.
At the time 80's-90's, the cnc milling and digital technology was somewhat limited to industry and just getting started in the art world, so we worked with the manual 3-d pantograph machines. Originally designed by the French in the 1700- 1800's, a good machine was accurate to a 1/16 of an inch within a 6-foot arch.
It was recommended "never" to enlarge something more than 4 times.
When you enlarge small mistakes they become much bigger mistakes!
An "accurate" large or middle size model is recommended for creating a superior enlargement. It also makes for less if any changing and cutting of the enlarged sculpture and armature; usually steel piping with foam. If the enlarged sculpture is distorted because of a faulty model it takes much more energy and more time and labor down the line to fix it. At the foundry we were always trying to be more efficient and produce a high quality enlarging for our clients.
There are certainly plus points with cnc machining sculpture to a larger size, yet there are some draw backs as well.
As you most-likely know, cnc milling is base on a digital scan of your model, it replicates the model in a urethane foam of various densities and the pieces are glued together. If an armature is needed, you can construct it by eye or use auto cad. But the foam parts must then be cut-up and placed and attached around the armature. Usually clay is then added as a skim coat to cover up the foam. By doing this you actually add additional clay to your surface. This may be okay for some sculptures, but if it is a representation figure this may not be so beneficial nor desirable.
The 3-d pantograph machine is basically two tables which turn with a chain drive. There is a ball joint on one end, on which the boom with two pointers sits, a counter balance balances the boom so there is no energy needed to hold the weight of the boom up. Once the machine is set-up, the first thing you do is weld or create the armature. The stylus on the model side traces the model as the pointer on the working end follows the trace in space. By doing this and turning the tables you can determine exactly where the armature must be placed and how big the armature must be. This takes out all the guess work. Once the armature is created foam or cardboard or in the past; wood lathing is applied to just under the working surface. This gives you freedom to apply as much or as little clay to the armature. In most cases we used 3/4" of clay, so the foam would be that distance below the finished surface. We then add the clay to slightly over the finished surface. Change the stylus to a wire loop tool, then scrape the clay as the machine traces the model.
In the end, the clay surface is exactly your finished surface not more or less.
I think when you add all the costs up for digital milling it is basically the same cost. Both methods don't capture undercuts very well, so refinement must be done by hand and eye. Again I am speaking as a figurative artist. Certainly artists of free form objects may benefit more from the digital technology while others may not. Every individual work of art has challenges and different tools to make the job easier.
I hope this helps!

Mike Keropian
http://www.keropiansculpture.com

[Blacksun]

Laser scanning with CNC milling in foam, followed by plasticene detailing is the easiest and fastest method I've used. Check out Blue Genie Studios

[Keropian]

Hello,

I have added some images of my 3-d pantograph or tracer or reducing/ enlarging machine on my website and discuss the process. I also compare some differences between the manual machine and the new digital technology.
I am currently setting up the machine in my studio and should have some more images in the future.

http://www.keropiansculpture.com/enlgmachine.html

[CritterSteve]

Here's another way (http://steveworthingtonart.blogspot.com/2010/02/how-this-way-of-enlarging-your-work-by.html) of enlarging.
Beats the photocopier and calculator method I've used before.
You can't turn your brain off since you're kind of doing it over from scratch, but your key measurements for numerous landmarks are nicely covered...