Virtual Kitty

You may be wondering what “Virtual Kitty” means. Compared to the original, physical doll, which you can touch and see, a virtual doll only exists as digital bits in a computer file. So why would I want to create a doll that doesn’t even exist in the real world? Because a virtual doll is the first step towards my ultimate goal of making the fictional version of Kitty a reality.

I love my antique Kitty doll (see Meet Kitty), who inspired A Tale of Two Hittys. I really enjoy dressing her and taking photos of her with my other dolls, but her fragile nature means that I have to be very careful with her. Wouldn’t it be great to have a copy of Kitty that I could handle without having to worry about damaging her? Also, Kitty is a paper mache doll with wooden limbs and a cloth body, but the doll in A Tale of Two Hittys is carved from wood with peg joints. It would be wonderful to have a doll just like the one in my story.

I could try to carve a replica, but copying the antique doll would be difficult. It would require meticulous measurements and a huge amount of patience. And carving such a small replica would be quite a challenge! Then I remembered the 3D scanner which doll artist Michael Langton used to make a copy of Ancestor Hitty for the Stockbridge Library (see Hitty Dimensions). I thought that if I could find a source for 3D scanning, I could do the same thing for Kitty!

After a Google search, I found a company called Haven Metrology. Metrology is the scientific study of measurement. Haven Metrology provides professional CT scanning and 3D surface scanning services. Their specialized equipment and expertise has been used by companies all over the country for engineering, manufacturing and scientific purposes.

But not all their projects are directly related to manufacturing. On their website, I noticed that they had scanned a sculpture for an artist in preparation for 3D printing. They also have used their industrial grade CT scanner for educational purposes. The Virtual Zoo project on their website provides free downloadable 3D files of some insects and small animals that they have scanned.

After seeing these projects, I was hopeful that Haven Metrology could help me to create a 3D scan of Kitty. I contacted them using email and got a response back from Keith Irwin, who told me they would be happy to scan my doll, and there would be no charge!

Keith first tried scanning the head with a CT scanner, which uses X-rays to see inside an object. Haven Metrology has an incredibly accurate CT scanner, the Nikon XT H 225 ST, which looks like a big gray box with a sliding door. Attached to the box is a control panel and monitor, to view the object inside. Bright warning lights are illuminated when the unit is in use. The device is about 8 ft wide x 4 ft deep x 7 ft high, and it looks quite impressive.

After scanning, Keith imported the data into a CAD program to see the result. Unfortunately, there were some problems with the scan, which left a large number of holes in the top of her head. The holes were possibly due to the combination of materials in the paper mache head. In this photo, notice the different layers in the cross section of her head after scanning.

*Desktop computer showing Kitty’s scanned head*

FUN FACT: WHAT IS KITTY MADE OF?
Kitty’s head is made from paper mache. I researched the process of making paper mache dolls (also known as papier mâché, which means “chewed-up paper” in French) in the book, The Collector’s History of Dolls by Constance Eileen King. Approximately 150 years ago, Kitty’s head was made by pressing paper pulp into multi-part, greased molds. As the head dried, it shrank away from the molds. After the parts were completely dry, they were glued together, and the edges were smoothed out with more pulp and gesso. Gesso is a material similar to plaster, made from gypsum or chalk mixed with glue. The thin layer of gesso gave the doll’s head a smooth surface for painting. After painting, a final layer of shellac (a natural resin made by insects) was applied as a sealer.

Since the first attempt at CT scanning was not entirely successful, Keith decided to try a 3D surface scan of the doll head. The 3D scanner has a round, flat bed, like a table, and a blue LED light scans the object. They applied an anti-glare spray to Kitty’s head before scanning. In this case, her hair interfered with the scan, as you can see in this photo.

*3D scan of Kitty’s head – courtesy of Haven Metrology*

Keith went back to the original CT data and spent several hours cleaning up the cracks and holes in her head. In this photo you can see a large crack on her forehead as well as a crack running through the shoulderhead up to her neck. Kitty was also missing the tip of her nose. After Keith’s restoration, the doll head looked a lot better. Keith then returned the doll and gave me the scanned data to use for my project. I can’t thank Keith enough for his generosity! He certainly went above and beyond to make a copy of my doll’s head, and he didn’t charge me a thing!

*Restoration of Kittys head – courtesy of Haven Metrology*

When I got home and unwrapped the doll, I noticed there was a white powder on her face. Keith told me this was the anti-glare spray, and he said that it would disappear with heat. But that didn’t seem to work. I tried wiping it off with a Q-tip and distilled water which helped a little. Finally, I tried spraying her face with “Mr. Super Clear,” which is a clear acrylic finish with a strong solvent. That restored most of her face paint, thankfully! But it also loosened the glue holding her shoulderhead on to the body. I decided that this might be the perfect time for a Kitty makeover. After seeing the cracks in her head, I realized how fragile her head actually was. A makeover would fill the cracks and stabilize her. I will share more about Kitty’s makeover in a future post.

My next decision was what to do the with data from the 3D scan. The file would still need some work before it was ready for printing. Guess what? I have never created files for a 3D printer, and my graphic design background is in 2D, not 3D. Which meant that I had to jump right in and learn a new software package.

As you might expect, there are many options when it comes to 3D software. The program I chose is called ZBrush, used by 3D artists for detailed sculpting of characters for video games and concept art. I like it because it has more artistic features than a typical CAD program. I found out that I could download a limited version of the software, ZBrushCore, for a small monthly fee. Then I spent over a month learning the software. I have to say, it has been challenging at times. The software is very powerful, but not especially intuitive. However, the company that makes it does have plenty of helpful videos, and I found a lot more on Youtube.

The original scan showed every flaw: there were tiny air bubbles inside the gesso and rough areas where her paint had flaked off, in addition to all the cracks in her head. I used ZBrushCore to further clean up and smooth Kitty’s head. This was painstaking work, but it made her look much more presentable. Here is a picture of the result. I call her, “OG Kitty.” I added a green line to highlight the mold lines on her head, indicating that she was made from a 3-part mold.

*“OG Kitty” after more restoration work*

I used “OG Kitty” as a template to make “NEW Kitty,” who would be based on the doll in my story. In A Tale of Two Hittys, the fictional Kitty doll was commissioned by Charles Dickens for his granddaughter, Mekitty Dickens, in 1868. She was carved from English Oak, with peg joints like the original Hitty doll. Most importantly, she needed to have a hairstyle from that era. I decided to sculpt an “Alice-style” headband to hold her hair back from her forehead, a style which was all the rage in the 1860’s (Alice’s Adventures in Wonderland was published in 1865). I made some other minor changes to the doll, lengthening her neck and making her face more symmetrical. But I kept her pudgy cheeks and chin and pert little nose. Here is “NEW Kitty.”

*“NEW Kitty” created with 3D modeling software*

NEW Kitty is a virtual doll. The contours of her head are composed of a mesh made from polygons. The points of the mesh correspond to reference points in 3D space. The original scan had over a million points, and the new sculpt has half a million. Fortunately, I have an iMac computer which is powerful enough to run the software I need to do 3D sculpting. The closeup photo shows the polygons that make up her mouth and nose.

My Xencelabs drawing tablet is also critical for this project’s success. Try drawing with a mouse, and you will see what I mean! The tablet uses a stylus for drawing, similar to using a pen on paper. Sculpting in ZBrushCore is not like sculpting in real life. Using the stylus, I can either add or subtract parts of the mesh. And I can distort, stretch, move or rotate the shapes, until I get the look that I want. Learning to sculpt virtually is certainly a challenge, but it gets easier with practice. The photo below shows the colored areas, called “polygroups,” used to sculpt her head, hair and headband separately.

*Separate “polygroups” on NEW Kitty sculpt*

To get the virtual doll back into the physical world, I needed a 3D printer. My son, Steven, agreed to print the doll head for me. He used a BambuLab X1-Carbon printer, which prints multiple layers of the object by melting and extruding a plastic filament onto the printer bed. Special software is used to slice the 3D model in preparation for printing. The actual printing process can take hours, depending on the size and shape of the object.

The first attempt failed due to it being printed too fast! I call her “Melted Kitty.”

*The first attempt at 3D printing: Melted Kitty*

The second attempt worked better and took about two hours to print. I will need to adjust the size a bit, because it ended up smaller than I wanted. Fortunately, that is an easy thing to change. Here is the completed 3D printed doll head.

After seeing the print, I noticed a few areas that need refining. The nice part is that I can make changes without having to carve a new doll head from scratch. When I am satisfied with the final design, I plan to paint the head and carve her a body from wood.

Now “Virtual Kitty” has become a reality. Although Kitty may look like a 19th Century doll, she has truly entered the 21st Century.

I want to offer my thanks to Keith and his co-workers at Haven Metrology for helping me with this project. Also, a big thank you to my son, Steven. I would not have been able to complete this project without you.