Friday, 15 February 2013


I love this striking photo by Sascha Hüttenhain and I wanted to use this as the inspiration for a new sculpture.

I had to use a bit of artistic licence to create a pose that would capture elements of the photo but remain printable on my 3D printer.

Here is the digital version of the pose that I wanted to try and print.

Capturing the Sascha Hüttenhain pose

Viewed from the other side

For the 'Pensive' sculpture, I had created a long hair style that would sit comfortably on the woman's collar bones, avoiding another potential printability issue. However, this model is holding her head sideways, so I knew that a long hair style wouldn't work.

Hair is a real problem when using the models in 3D posing software. It usually consists of multiple flat layers combined to give the illusion of depth. This may work for 2D images, but 3D printing demands real depth with solid models and the standard hair add-ons don't work.

One of the most useful techniques I have tried, is to export a hair style as an .OBJ file, import it into Blender and then use the Shrinkwrap modifier on it. It isn't a completely automatic process yet, because it still needs a fair degree of tweaking, but it is much better than attempting to print the original hair model. The finished hair object can be combined with the rest of the body with a Boolean Union join to create a single watertight mesh which the slicing software can cope with.

This model presents several new challenges. The head is tilted sideways; the legs are at a shallower angle; the left elbow is beside the knee, not resting on it; the hands are being held horizontally, one above the other.

All of these factors led me to the conclusion that I would have to turn on automatic support in my slicing software. I would also have to print with ABS plastic because of the way that the support elements will have to break away from the model, leaving the minimum of scarring. I fully expect to have to do some post-processing work after printing this model.

I generally use Slic3r for turning my 3D models into printer instructions, but I don't find it that good at generating support material. Recently, I have had more success with using Kisslicer when I need good support material. Printing models with a small footprint, and this includes support material, is sometimes more reliable if it is laid down on a printed raft, rather than directly onto the printer bed. 

In Kisslicer, I turned on the Raft option and set the Support material density to medium.
I set the model height to 8 cm and the layer height to 0.2 mm, giving a total of 400 discrete layers.

Here is a close-up preview of the printer file rendered by the excellent printer controller software, Repetier-Host, showing the raft (under the feet), the support structures (under the legs) and the individual layers of the model.

Repetier-Host preview render

And here is the 3D printed version.

Printed in grey ABS at 240°C, 0.2 mm layer height, waiting for support material to be removed.

And now, following removal of the support material and surface blemishes.

Removing the support material



The 'Sun worship' model took me at least five attempts to get a decent print from, but having finally got it to the point where I was happy with the output quality I decided it was time to move on and try a different design.

There are many factors to consider when designing a model for printing on a 'fused filament' type of 3D printer, like a RepRap or Makerbot. One of the most important ones is the the need for 'support material'.

The printer starts printing the bottom layer onto a flat bed (usually heated to 100°C to make the plastic stick to it) and then proceeds to print each successive layer on top of the one underneath. This works fine for blocks with straight sides and can even cope with sloping sides of up to 45 degrees where each layer projects out a bit further than the one below.

But in real life, things stick out at all sorts of angles and this presents a problem. Just take a look at the middle of your face and imagine how difficult it is to print chins and noses. The printer is squirting hot, runny plastic filament downwards from the nozzle and needs something to extrude the plastic onto. If there is nothing there, the string of plastic will just hang down in mid air instead of following the path that the nozzle is tracing as it draws.

Sun Worship

One way to address this problem is to create support structures which are not part of the sculpture, but are solely intended to provided a surface for the upper layers to land on. 
Another way is ensure that the model has no projecting angles shallower than about 45 degrees.
Look again at the Sun worship model and you will see that all of the limbs, the torso and the head have been carefully posed to ensure that there are no unsupported regions.

I decided that my next project would be a nude sculpture of a woman standing in a pensive pose, one knee slightly bent and arms held close to the chest. 

After working through a number of iterations I arrived at this pose.

Again I spent a considerable amount of time fixing the mouth and eyes and creating a customised hair object.

It turned out that there were several problems with this model. Firstly, the points of the elbows and the chin had nothing beneath them so I decided to add some small support blocks for removal after printing.

In this picture, you can just make out the small disc between the thumbs, as well as the triangular elbow supports.

This should have worked in theory, but in practice the chin support was too thin and failed to print correctly, while the elbow supports ended up too close to the model and caused an unsightly mess.

The other big problem was that my printer can only go up to a height of 13 cm and even using the full print height the model still ended up quite small.
This would have been OK had it not resulted in the fingers becoming too thin to print correctly.
Here is one of the early attempts demonstrating some of these problems.

I made a number of significant changes to try and improve the quality of the print.

  • Moved the elbows closer to the abdomen and removed the support blocks
  • Repositioned the thumbs under the chin
  • Slightly fattened the fingers and thumbs
  • Increased the height of the model to 20 cm
  • Printed in two halves, with a connecting pin to join them back together
The fingers are little bulky and the seam is still visible but this is straight off the printer, with no post-processing work.


Incidentally, you can see the legs of this model being printed in the very first picture of this blog.

Tuesday, 5 February 2013

Welcome to 3D Printed Nudes

Home 3D printer ownership and use has exploded over the last couple of years. These small but powerful machines are capable of creating solid objects by melting plastic filament and depositing it precisely in thin layers, building strong, solid shapes that can be both functional and aesthetically pleasing.
Printers can be built at home from a kit for about $750, or purchased ready to use for about $2000.
Almost all of the software needed to create and print digital 3D models is available as open-source freely downloadable files.

The 3D printer in action

Why print nude sculptures?

  • Classical sculpture has used the nude human form as subject matter for thousands of years. Humans innately find beauty in representations of the human form.
  • The smooth, subtle, sensuous curves of a naked body present a real challenge for machines that are typically used for making mechanical objects based on digital models.
  • Many great statues can be captured for printing using an ordinary digital camera and a free online service such as Autodesk 123D Catch.
  • 3D modelling software already offers the capability to create digital compositions that can be exported in a printable format, but these files are not generally printable without extra work.
  • Adding clothing on top of the models, significantly complicates this process. Making printable nude sculptures is both pleasing and much simpler.

There are many challenges to be overcome and I aim to make this site a place for sharing ideas to improve printing quality as well as a way of sharing some successes and failures.

Here is a new sculpture called "Sun worship" that was processed in Blender to make it ready for printing.

Sun Worship - face detail

Sun Worship - hand detail

Sun Worship - feet detail

Sun Worship - with ear-buds for scale