Tuesday, 18 June 2013

Body Language

I have just completed one of my best projects so far. It was inspired by another great Bruno Birkhofer photo called Body Language.

I took special care with the pose modelling to capture the lines as faithfully as possible, carefully placing the limbs as close as possible to each other without overlapping. I reused a short hair style of my own creation.

Here is a screenshot of my version in Blender.

The next important step was deciding how to print it and what kind of support to generate. I used Kisslicer to generate the printer files again, because although a new version of Slic3r has just come out with supposedly much improved support generation, I haven't had time to test it yet.

I decided to to make one change from the settings I used for the previous Birkhofer print and that was so go up from Medium to Dense for the support layer, just to see what would happen.

The other genius idea I had was to turn the print vertically for printing, which changed the position and amount of support material required. If I had printed the model exactly as it appears in the picture above, all of the chest and head would have need support underneath it. By rotating it to a much more vertical angle almost none was needed in these areas.

I was so impressed by the new settings that decided to make another video of the support removal process. You can see how my preferred tool is a flat bladed screwdriver which breaks the weak bonds between model and support with less risk of damage to the delicate areas. The support was certainly more dense than before and, in my  view, held the model better whilst still coming away cleanly.

Support removal video

Before and after smoothing

Finished print

Sunday, 9 June 2013

Bruno Birkhofer

Last year, Thingiverse member, richgain, demonstrated the use of a camera and a 3D printer to make copies of the works of great artists like Auguste Rodin when he published his version of Crouching Woman. The resolution is not great and his method of using point cloud renderings from multiple photos loses a lot of the fine details but the essence of the piece is still there in the lines that the body describes. 
This, to me, is the point of sculpture as art.

One of the artists I have recently discovered during my research is fashion photographer, Bruno Birkhofer. I share his passion for the artistic shapes and lines that can be described by the body held in a beautiful or unusual pose. He captures his models photographically and freezes the pose in time but also selects just one angle from which the model will be viewed. My attempts to convert these great photos into 3D models aim to allow these forms to be appreciated from any direction and angle.

Looking back over the work I have done so far allowed me to reflect that one of the pieces I most enjoyed creating was Metamorphosis. I still think it's a strikingly dramatic pose. So, when I saw this Bruno Birkhofer picture I immediately recognised an opportunity for a new sculpture.

I have started work on the pose and, although it still needs some refinement, I'm pleased with the way it's progressing. The next stage is to begin cleaning up the mesh to make it printable and finish working on the hair.

I decided to print the model at a higher resolution than I used for Recline and opted for a 0.15 mm layer height. The print came out very well with only the underside of the horizontal surfaces looking rather ragged. This should improve with the final smoothing in acetone vapour. 

Before smoothing

The finished sculpture

Tuesday, 4 June 2013

Recline further

I decided to persevere with Recline and try to fix some of the problems.

Following an invitation from Sublime to try his calculator (see the comments in Recline), I learned that my setup could work better at 0.2 mm layer height if I increased the extrusion width from 0.4 to 0.48 mm. That should certainly help to improve layer bonding somewhat.

I also reasoned that the delamination in the first print had been caused by excessive part cooling with the fan. I know, I know. ABS isn't supposed to need a cooling fan but I still believe that with steep overhangs it just prints a bit better with one; I just had it turned up a bit too high.
The next problem to work on was the fingers. I started another couple of prints and both times the fingers failed again. Something different was going on here.

I thought about this for a long time and eventually came up with three ideas for possible solutions.
Firstly, the way that I had splayed the fingers out made the overhang angle more than 45 degrees. Changing the pose slightly to make the fingers more vertical should help.
Secondly, I had changed the support gap setting in Kisslicer from 0.5 mm to 1 mm to try and make it easier to break away; I suspected that this was actually making the support less supportive, so I put it back to 0.5 mm.

Finally, it dawned on me that the only thing supporting the fingers was the weak interface layer attaching them to the raft. This hadn't been a problem with Curl because there were relatively large areas attached to the raft but this print was quite literally clinging on by its fingertips, and in the end the lateral drag of hot plastic from the rapidly moving nozzle was proving too great for the weak bonds. The solution for this print was to abandon the raft and find a better way to get the fingertips to stick to the bed. 

One option I considered was to print the model on a plinth. This would provide the strongest and most reliable base but wasn't really in keeping with the rest of the series so I decided to keep it in reserve. 
Eventually I resorted to my favourite method which has worked well in the past. I went back into Blender, opened the model in point edit mode and used 'Box select' to highlight all the points in the bottom millimeter of the model and then used Scale Z 0 (zero) to flatten the bottom of the model and finally moved all the selected points up a little to the most natural position.
A liberal splash of ABS juice on the printbed and I was ready to have another go.

This time it went much better. No serious delamination at all and the fingers are looking much more solid. The left thumb appears to have shifted and reconnected at the base, but this should be relatively easy to repair.

Now I just need some time to do the support removal and acetone vapour bath.