3d-printing my frog!

 

The background

More than ten years ago, I was learning 3d and how to properly animate a character. I created Korky the frog to help me learn modelling, texturing, UV editing. Then I used Korky as a base to learn rigging, character animation, to do a lot of test and to practice. Finally I released the short movie “The Frog 2” to learn rendering, compositing, etc. So Korky acted as a 3d training guinea-frog to me.

Some months later, Korky got me my first real job, when a film maker saw the animated creature online and called me to join a team working on an I AM video clip. It was the start of an exciting career that got me creating and working on many different characters.

However, Korky always remained my fave creature. He looks great with all his colors, he’s cute, endearing… and it’s not someone else’s project, it’s a personal project. He became kind of a mascot for my 3D freelancing business.

Back in 2002, during the Christmas vacations, as I was putting the final touches on the short animation clip, I would never imagine this virtual character would someday exist as a real life object, as a statuette.

We all know our word processor’s “print” menu. Who would have thought that, someday, 3d applications will get a “print” menu too? Thanks to the incredible advances in technology, it is now possible to print a 3D scene into a 3d object!!

Last spring I had already printed the frog into a 6 cm high white plastic piece. It was fun to do, but the result was not so spectacular. So when I learnt it was possible to print in color, I was immediately filled with enthusiasm for another try!

 

Putting together the 3d files

First I prepared my scene for the 3d prining and got Korky into a greeting pose.

It was a bit difficult to get a file that was compatibe with 3d printing and that retained textures. If you’re looking to do the same thing, here are some tricks that could get you started. Let’s start by what one should do Inside the 3d app. Mine is Softimage XSI.

– Have the original rigged character under a model null and have the exportable character under another model-null.

– It’s easier to deal with one single merged mesh, a single UV set, and a single texture for the whole character body. So if your character has different parts (the eyes, for example), a merge is necessary. Use create > merge and transfer the UV & materials. In my scene, Korky is a single mesh, even its eyes. But the plinth and the text are 2 other objects.

– Once the merge is done, delete all clusters and use a single material for the whole character.

– The object centers must be at the world’s center (0 in XYZ), even if it means the center of the object would be outside the mesh.

– After the OBJ file will be created, you’ll need a 3d objects viewer to check the result. So for the textures, you have to choose an image format that will be compatible with this viewer and you may need to convert the original texture image to another format. In my original scene, I was using Targas and Photoshop files.
Meshlab : does not accept TGA and PSD (according to my tests in december 2014). TIFF does not seem to work neither. JPEG works, and I heard PNG works too, but I’ll have to try it.
Microsoft 3d builder is preinstalled in Windows 10. It’s a nice viewer but the axes are not set like in XSI with the Y up. It accepts PNG’s.
Softimage can be used as an OBJ file viewer but it’s better to check the 3d file with a viewer that have the same behavior and limitations as 3d printing applications.

– You’ll need to export the meshes through OBJ. The geometry approximation kind of subdivisions are not taken into account by the OBJ exporter, so you’ll need to use the create > subdivision menu, and again, transfer the UV & materials. I noticed that when you merge first then subdivide, everything goes well, but if you do it the other way around, you’ll get UV problems on some spots.

– Here is a render of the frog just before its export to OBJ:

– Select only the object you want to export then file > export > OBJ. Check the options to export materials, etc.

– On the hard drive, we get an OBJ file, a JPG file and a MTL file. MTL is not a texture, it’s just a tiny text file containing the path of the texture and some parameters for the materials. I noticed long paths, or relative paths, did not work, perhaps because of the spaces Inside the paths. I’ll have to do more tests, but for now, to be sure it would work, I just put the 3 files Inside the same “Korky” folder, and changed the texture path inside the MTL file to keep only the JPG’s file name.

– Then I open Meshlab and import the OBJ just to check if everything is OK. I can also re-import the same OBJ in Softimage to see everything’s fine.

– Last step: put the Korky folder on a USB stick and bring it to the 3d printing shop!

 

3D printing service choice

So I had to choose a shop for the 3d printing. In my town Antibes we have the chance to have two 3d printing facilities:

– Navlab: so far they print only plastic but printing is VERY cheap. I’m also a good friend of the team as I use their co-working space several days per week. NavLab is a fablab: a club of passionate persons who meet to help each other build prototypes, imagine inventions, repair devices, follow trainings or just gather for a coffee, speaking about new techs. I love this place!

– TridyMaker : more pricey, but you get the satisfaction to see you character in a color version!! 🙂 And Tridymaker’s team is cool.

 

A long weekend

Tridymaker took my file on friday and they seemed as enthousiast as me about printing the frog. Problem was… I had to wait untill monday! I couldn’t wait to see Korky in real life and the weekend seemed long. But yesterday, here it was at last, standing on their table!

Printing specs: color print through ProJet 4500. Size : 98.24 square cm. As far as what I’ve understood, the Printer uses a material called “VisiJet C4 Spectrum”: a plastic that’s colored through ink jet. More info on how this printer works here.

I was amazed by the result. All the colors and details I’ve done in the 3d were here. I even recognized the bumps on his back that I modelled after its froggish skeleton. More photos:

 

The frog is exhibited at NavLab. I intend to print more characters in the future.

Thanks for reading and see you soon,

David