Saturday, 19 July 2014

Shame

I'm going to try and create a sculpture based on this picture next. I like the off-balance lines, the hidden face and the twisted shape.



The photo is by Tomas Rucker and is called 3 in his White series of nudes.

Here's the model I have created so far, viewed in Blender. The pose is clearly not identical but you can see where it takes its inspiration from.



When I came back to work on this pose I wasn't happy with it. The sinuous nature of the original pose had almost completely gone and the new hand position somehow changed the story. I decided to do some more work on the posing.


I thought it might be interesting to document the steps needed to make a posed model printable.

Hide the hair
Remove the eyelashes

Circle select eyes and mouth in side view

Shift-H hides everything else. Trim out the eyes and mouth and close up the holes in the mesh.

Now we need to deal with overlapping limb parts. There are several ways of doing this.
1. The quick and dirty method.
Use Autodesk's Project Miller to re-skin the visible external surface which hides any internal overlaps.
2. Use sculpt mode to flatten overlaps from the inside.
3. Use Boolean union to eliminate the overlaps. This option is interesting but doesn't work on a single mesh with overlapping parts. So why not just chop up the parts into separate meshes? Worth exploring, I think.


More to come.

Monday, 23 June 2014

Brenda Lynn

This photo of Brenda Lynn Acevedo, found on the Bella Donna blog, caught my eye for a couple reasons. Firstly, having her arms (and, in my imagination her legs) held either flat or vertically makes them easy to print without support; and then of course there is the way that her breasts gently rest on the floor giving them a profile that reminds me of a Piet Hein superegg (go and look it up and you'll see what I mean).




The fluid nature of (natural) breast tissue means that it naturally reshapes itself in response to gravity. (Of course, the same is true of all fatty tissue, but the models in these photos don't usually have much surplus fat in other places, so this issue generally only affects the breasts.) Character modelling software allows you to position the limbs, trunk and head in anatomically plausible positions, but also allows you to change the shape, size and position of the breasts. One thing that it doesn't do very well though is to model the impact of gravity on mobile breast tissue; there are add-on pieces of morphing software that give an additional level of control, but nothing I have found yet that mimics the effect of gravity on natural breasts in a reclining position.
So, after exporting the best pose I could manage from the posing software, I started sculpting in Blender until the breasts had a shape I was happier with and which I was ready to try printing. 


Feeling lazy, I used the clock rewind trick to bring Project Miller back to life again and quickly generated a single watertight mesh from the multi-object base and then did one more smoothing iteration.
I used Simplify3D for the slicing and made sure there was plenty of support material around the right arm so that the small point of elbow contact with the bed wasn't put at risk of failure.
I decided to use a nice wood-coloured PLA from 3D Filaprint and after a long 16 hour print this is what the printer produced.








Opinion: I'm generally very pleased with this one. There are couple of areas that could be improved - some distortion around the heel, and rather too little support material in the small of the back and between the shoulder blades.

Postscript: I decided to adjust the layer positions and try a reprint. This one came out even better.


Sunday, 8 June 2014

Yoga interrupted

My third and final sculpture this week is a mashup of two more photos I found on Belladonna's Tumblr blog. I wanted to use the top half of this photo ...




... and the bottom half of this photo ...




... combined in a single pose.

Getting the feet into position was the most difficult part.




I am already a total convert to the idea of 'micro-layering - printing the external skin at 0.1 mm layer height but the support and infill at 0.3 mm layer height, so infill is only laid down every third layer. One of the new features I have been experimenting with is 'infill zoning'.
  • Starting at the bottom, Zone 1 uses 25% infill.
  • The top surfaces of the calves, thighs and feet are in Zone 2 and use 40% infill.
  • The trunk, arms and head in Zone 3 revert to 25% infill.
  • The top of the head uses 50% infill.

You can just about see the four zones in this reverse cross-section view (click to enlarge).



This uses less infill material where it is not needed, saving time and money, but increases the level of internal support where important top surfaces need to be laid down smoothly. 








The support material generated by Simplify3D worked reasonably well but left the undersides of the elbows and calves a little rougher than I would have liked.

Saturday, 31 May 2014

Leaning back

The second new print was inspired by one of the many great pictures I came across in Bella Donna's Tumblr blog. I should warn you that it is NSFW, but it is a beautifully curated collection.



This is one one of many archive photos and sadly there are no details of the photographer. Performing a Google image search didn't help me on this occasion.

There are many invisible details that I have had to use my imagination for, such as the position of the feet in relation to the head and the expression on the model's face. It was a great challenge though and resulted in a nicely printable model.

Here's a side view of my digital version in red-cyan anaglyph mode (which I've just discovered you can do in NetFabb!). Dig out those glasses and have a preview.



This model just happens to be close to the exact proportions of my printer's printable volume, so this could turn out to be one of my largest models yet. At a layer height of 0.1 mm and a total print height of 125 mm this is going to take 18 hours to print. Keeping everything crossed for this one!

OK, printing successfully finished and here she is (iPhone included for scale).






Reflections

Here is the first of three new prints I have been working on recently.



'Reflections' came to my attention when Bruno Birkhofer posted a different picture on Google+ last week. All his pictures are beautiful but, once again, it was one of his black and white portraits that inspired me to try another sculpture.

Modelling the pose in my favourite character modelling program was fun, as usual, but it proved particularly tricky to place the hands in exactly the right position. Several of the joint movement ranges have to have their range limitations turned off just to get close. 

In a moment of over-zealous optimism I decided to replicate the model's facial expression and kept the eyes closed but the mouth open. This involved a significant amount of cleaning up in Blender for a detail that ultimately proved too small to show in the final print. 



Not to worry - one day I may be able to sell these models and perhaps I'll even be able to afford a nice high-resolution DLP printer like the Kudo3D and then they will look even better.

I'm now getting the hang of using Simplify3D to slice my models so that the support material is placed where it's needed. The only thing I got wrong this time was placing insufficient support underneath the ponytail. The tip broke free during printing but fortunately the print managed to correct itself leaving enough to look reasonably OK.

Here's a couple of photos of the final print using translucent coffee-coloured PLA from 3D Filaprint, at 0.1 mm layer resolution with support enabled.

Close-up reproducing the pose in Reflections


The full model, showing a nice reflection of its own


Monday, 5 May 2014

Loopback

Another new pose inspired by this photo I found on Pinterest. The original photograph was taken by Mikhail Nekrasov.
(UPDATE - see Mikhail's comment below)



Character posing software really seems to struggle with extreme shoulder positions and this one was no exception.

I wanted to use Simplify3D again to make use of the excellent support material it generates. However, importing the finished model processed in Blender seemed to show artefacts generated by the eyes and mouth. Cura's Fix Horrible option still does a better job then Simplify 3D in this regard but unfortunately there is no function to export a 'fixed' file.

My standard solution in the past would have been to use Project Miller, the great experimental tool from Autodesk Labs, but it expired and ceased to work on 1st April 2014. Not funny!

Just on the off-chance, I reset my PC's clock to Feb 2014 and started the program up again. Bingo! It works perfectly. I fixed the model, exported a new STL file and loaded it up into Simplify3D. The new gcode looks clean as a whistle. Ready to start printing.

After a 12 hour printing run the print quality is already looking great.








This black ABS plastic always looks nice after smoothing with acetone vapour. Some of the horizontal banding caused by the print layers can become a bit more prominent though, so after breaking away all the support material I decided to try something new and gave the whole model a light sanding with a fine grit sandpaper first.






For models like this, I recommend doing the acetone vapour treatment in two halves. Holding the upper half of the model, I gently lowered the legs into the vapour for about 20 seconds and then set it aside to harden on a ceramic tile. Once the surface was hard to the touch several minutes later, I held the model upside down in the vapour and treated the head and body the same way.
This method gives a nice even smoothing without risking melting the lowest parts into a puddle of sludge.







  

And here's the original again.  How did I do?



Wednesday, 23 April 2014

Photo finish

Here are some photos of the prints from 'Casual undress' and 'Crouch' after finishing with the acetone vapour smoothing process.