Princess Power: Bringing Cats to Life with CAD

In Norse mythology, the goddess Freyja rides a beautiful chariot pulled by two cats. It just so happens that Princess Freyja, the 2021 recipient of the SOLIDWORKS Magic Wheelchair build, loves cats more than just about anything in the world.

When the team first met Freyja, she told them about all of her likes, and they decided to make her princess dreams come true. The cat question was on the front of everyone’s minds.  Early on, the team decided to create a princess castle, but how could they incorporate cats into the design? Chinloo Lama brought up the goddess Freyja fact, and Rob Jost, SOLIDWORKS Product Definition Senior Manager and renowned cat lover, jumped on it. To incorporate cats into  Princess Freyja’s final costume, she would ride in a castle in the clouds, pulled by two cats, just like her goddess namesake.

For Rob, not only was this a chance to make something new, it was also a chance to test the limits of the Sub-D modeling solution found in 3D Sculptor, xShape. Rob is an expert SOLIDWORKS user, but he knew the next-generation, browser-based tool xShape was the right call. Trying to model something organic like a cat in a parametric modeling tool like SOLIDWORKS would be a really lengthy process with a very long feature tree. Rob said, “I needed something to more or less sculpt the shape, rather than create it from sketches. xShape was the only obvious tool for me. And,” he added, “as someone who works on xShape, it was a great opportunity to test and push the boundaries of the software.”

Rob had never dreamed of making a cat in CAD software before. Using the Sub-D tool made him to think differently about the design compared to how he would use parametric tools. “Once I got my brain focused on how to make a cat, the tools were all there in xShape,” he said. “To be honest, it was a lot of pushing and pulling and sculpting, and then some modifying. I only used about 20 percent of the tools we have available in xShape and it worked great.”

For the cat bodies, Rob found pictures of cats online. He put them into the background in xShape and sculpted the cats from the references. When it got down to the details, like features around the cats eyes and noses, Rob turned to the two real-life cat models he had at home: Milo and Fonzy.

It’s one thing to create a cat sitting or standing still, but the cats that pulled Freyja’s castle needed to have movement and energy. They needed to look like they were in motion, pulling the castle. Getting there took some trial and error. Rob’s first model was a test of his skill to see if he could even make a realistic cat, and it looked more like a cylinder or a Tootsie Roll. The team agreed the pose wasn’t energetic enough. Rob went back to the drawing board, watching videos on YouTube and studying his own cats slinking around and pouncing on the light from a laser pointer.

After iterating in xShape, Rob created two domestic shorthair cats bounding forward in mid-run. They were hyper-realistic and their bodies looked very similar to Freyja’s own cat (and, of course, to Rob’s cats).

Once the designs were completed, it was time to face a different challenge: fabrication. The initial idea was to machine the cats out of foam and suspend them from the front of Freyja’s castle with hard wires, similar to a cantilever. The wires would be covered with fabric and look like harnesses or reins. Rob sent the cat head model to Santiago Laverde in Texas to for a proof of concept. Santiago has a CNC machine at home and is a foam milling expert. He was able to create a cat head out of foam, but there were some concerns. Thin pieces of foam can break easily, and Rob worried the cats’ tails and legs could break off. Foam milling would also mean less accurate cuts and a lot more sanding and handwork for the team in Waltham. Rob wanted the cats to look real, just as real as they looked in the CAD, and he wanted them to be sturdy. So he sliced the cat designs and turned to 3D printing.

3D printing allowed for more precise real-world cats. The pieces matched Rob’s designs to a T, and he put everyone’s printers to work. In the two weeks it took to 3D print all the cat parts, Rob utilized all of the available 3D printers in the 3DEXPERIENCE Lab, along with Annie Cheung, Gabe Enright, and Sal Lama’s personal 3D printers in their homes. When each piece finished printing, Rob took them and glued them together. Once they were glued, he barely had to do any post-processing—just a little sanding and filling in cracks.

A note on cat eyes: Cat eyes are very distinct. Rather than paint them or try to create them in-house, project foreman Annie Cheung went online and purchased a variety pack of different colored cat eyes for doll making. Rob had to figure out a way to add them to his model, so he measured the plastic eyes and went into his CAD to make sure there would be space for the extra parts to nest inside the head. In the CAD, he broke up the cats into pieces and cut off the face from the front just behind where the eyes would be. Rob cut out a hole so, once 3D printed, he could insert the eyeball from the back and the rounded end would protrude from the front. Then he glued the face onto the head and the posts on the back of the eyeballs held the eyes in place, both with his changes to the design and the glue itself. Rob wanted the eyes to be orange and yellow, but the team decided to go with purple and blue so they wouldn’t be scary and would fit with the princess color palate.

Over the course of two weeks, Rob watched his cats come to life. Once they were all printed and glued together, he could pet the cats, just like Milo and Fonzy at home. They looked almost identical to his own, real-life cats.

However, a real-life domestic shorthair weighs between 6 and 12 pounds. The 3D printed cats weighed over 25 pounds. The idea to hang them in front of the castle with wires? No longer feasible.

“That’s how we came up with ‘The Sled,’” Rob said. The Sled was a wooden platform with pipes sticking out of it that was attached to the front of the castle for the cats to rest upon. Sal Lama handled how it would attach to the costume’s frame. The Sled was designed so when the costume was disassembled, it could be folded up and remain compact for storage. Freyja’s family could remove the cats, foam castle, and pipes and then fold the frame up together so it would minimize space.

To create The Sled, Rob took two pieces piece of machined wood and stuck pipes in the top and added casters to the bottom. He also successfully entertained the team members and got an arm workout by cutting the pipes himself with a hacksaw. He bored holes into the cats’ bellies so the 3D prints could be placed on the pipes. Finally, he put the printers to work again creating 3D-printed fixtures to hold the cats in place so they wouldn’t spin on the pipes.

With the cat logistics figured out, there was one more thing to do to bring them to life: paint them. Rob is super confident in his skills as a designer, but not so much as a painter. He didn’t want to mess the cats up, so Meaghan Murphy and Vincent Liu joined the team as the resident painters. As cat lovers themselves, they had a ball painting the cats contrasting colors. One cat looked like a black and white tuxedo cat, similar to Freyja’s cat, and the other one was made more fantastical: white with fuchsia tiger stripes going down the back.

All that was left were the final touches. Rob bought fake cat whiskers online and took a hand drill to the cats’ faces. He drilled in tiny holes and used crazy glue to stick the whiskers on, then trimmed them down to make them more realistic. “It was one of the touches that made you stand back and say, ‘Oh my God, it looks so real!’” he said. With the paint and the whiskers, the cats looked just like his CAD models. Chinloo finished the cats off by creating fabric reigns and tying them around collars she made for the cats’ necks. In the end, the cats truly looked like they were pulling the castle along, just like goddess Freyja’s chariot.

When the cats were finally complete, Rob was thrilled. “I remember thinking, wow! I can’t believe we actually designed and created the cats using CAD software.” Rob visits SOLIDWORKS users all the time and has seen all types of machines and products, including organically shaped designs like bathtubs and coffee makers. But he’d never seen anything as organic and smooth and lifelike as the cats. He never believed it could be done and it was really cool to see them brought to life.

What was cooler? Freyja’s reaction. At the reveal, when the team lifted the Magic Wheelchair drape off of the costume, Freyja’s made a bee-line to the cats. They were her favorite part of the costume.

“It really validated that we made the right decisions,” Rob said. “When we realized how heavy the cats were going to be, we needed to pivot and make some hard decisions. One of them was asking the question: do we still include the cats or do we drop them? We had a hard deadline and we couldn’t push the reveal date out. We stuck with it, pulled together in time, and got the cats on there.”

For Rob, seeing Freyja’s reaction made it all worth it. He found creating the cats to be very fun and educational. “Magic Wheelchair is a very rewarding experience,” he said. “Doing something for a deserving child is really rewarding for everyone involved, the child and the build team.”

On top of that, Rob appreciates getting to use SOLIDWORKS products the way a customer would. “We’re the people in charge of making the software better,” he explained. “It’s a learning experience. Millions of people who will benefit from us doing these projects are our customers, because we learn great ways to improve the software. Magic Wheelchair is awesome.”

In loving memory of Fonzy Jost, who passed away in 2022.

Help support Magic Wheelchair and amazing kiddos like Freyja!

SOLIDWORKS is proud to help the non-profit Magic Wheelchair achieve its goal of providing kids in wheelchairs with epic costumes and experiences. SOLIDWORKS and the 3DEXPERIENCE Lab funded Freyja’s costume build in its entirety, but we invite our readers to support Magic Wheelchair in Freyja’s name! If you visit this page, you can donate directly to Magic Wheelchair and help support them all the lives it touches with its great work.

Freyja is no stranger to magic—every year she has a magical time in the mountains at Double H Ranch, a camp in the Adirondacks for children with serious medical conditions. Like Magic Wheelchair, Double H Ranch promotes inclusion. Inclusion is important to Freyja and her family, and you can see how happy the camp makes her in her bright smile at the top of their webpage. We encourage you to discover Double H Ranch and donate to it as well, to help kids like Freyja experience the fun that can be had at summer camp!

Learn more about Freyja here.

Read about our other Magic Wheelchair builds here.


Sara Zuckerman

Sara Zuckerman

Sara Zuckerman is a Content Marketing Specialist in Brand Offer Marketing for SOLIDWORKS and 3DEXPERIENCE WORKS.