Showing posts with label Cura. Show all posts
Showing posts with label Cura. Show all posts

Sunday 20 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.



Then 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.

Hair models in character posing software are almost always totally unprintable items. I have found that the quickest way to make them printable is to use the ShrinkWrap modifier on a dense Isosphere placed in a position surrounding the hair model. Then using the project option in a negative direction, you can send all the points of the sphere inwards until they meet some point on the hair, leaving you with a single water-tight mesh. Some fairly intense smoothing removes all the jagged edges and leaves a very passable, and printable, copy of your chosen hair design. 



This just needs Boolean merging with the head which usually works OK, as long as the eyes and mouth have been fixed first. 

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.

I started at the feet and worked upwards, using option 2 to eliminate any of the areas where the mesh of one limb poked through another. There is a typical example where the thighs cross. I used Box select to highlight all the affected vertices and then Shift-H to hide everything else.



From the inside you can see the bulge of the left thigh poking through into the inside of the right thigh, and vice versa.



I started by changing from Edit mode to Sculpt mode and then using first the Flatten brush and then the Smooth brush on the bulge to make it disappear. 



By working from both sides I could keep the contact area flat.



This works well where there is a small bulge across a large area, but is less effective where a larger, more complex part needs removing. So for the intersection of the arms and the left breast I decided to try a different tack and used option 3.

I rotated the model by 35 degrees around the vertical so that a horizontal plane would neatly bisect the upper arms. I then loaded the model into NetFabb which has a very nice plane cut function which provides a kind of X-ray preview of the slice before making the cut.


My cunning plan was to slice the model into a number of separate parts, make each one into a separate water-tight mesh and then Boolean merge them back together thus dealing with a number of complex overlaps at a stroke.



After making the cut, each half needed to be saved separately. The forearms, in the lower half, could then be selected and split off into a separate model. Here is the main torso piece.



My plan worked almost perfectly, only failing when the last piece in the sequence refused to Merge with the rest. I suspected that this was because the Boolean engine was struggling to cope with the intersecting parts and closing the loop of a torus and recognising the relative inside- and outside-ness of both ends at the same time. I fixed that by making another thin cut that took a slice out of the arms in an area with no complex intersections. Using that slice as the final merge then worked successfully. 

I added a simple bevelled cylinder to the base to make a stand. Eventually, I had reached the point where the only crossed meshes remaining were in both armpits. I spent a fairly lengthy mesh-editing session trying to clean up the mess but finally decided to take the easy way out and used Project Miller to re-skin the model for me. Don't know what I'd do without that bit of kit!

The main reason for going to all this trouble with the model was so that I could use Simplify3D as my slicer. Cura is better at handling faulty meshes but Simplify generates better support material that breaks cleanly away after printing.

I had intended to print this model on my tall delta printer, but it isn't coping well with this hot weather and the motors seem to be prone to skipping steps. So I went back to the Mendel90 and printed a small test version.

3D printed version in coffee-brown PLA before and after removing the support material.




Just like Pensive, one of my earliest works, the fingers are only slight wider than the extruded filament at this scale. It really needs to be printed twice as big as this. As soon as the cooler weather returns I'll try again on the delta printer.

Monday 21 April 2014

Casual undress

Right, I think it's time for an Entiresia original.

I have a pose in mind and I'm going to have a go at creating it from scratch. I want the woman to be relaxing casually on her side, head propped up on one arm with the other hand reaching forwards and resting on the floor. I also want the knees tucked up a bit and both feet resting on the floor.

I started by positioning the right arm and then the head and neck. Next, I added a bit of forward bend, lateral flexion and slight rotation of the spine, to make the right hand side form a straight line, as if lying on the floor. The model was then rotated almost 90 degrees to the right, into the reclining position. The breasts were repositioned slightly to show the effect of gravity pulling from the right side and then the legs and the left arm were placed in contact with the floor.



This pose was also designed with 3D printability in mind, so should require a minimum amount of support.

I did the slicing in Cura with my usual setting of 0.15 mm layer height and 25 mm/s print speed, although I think I could have gone a bit faster. The steep angle on the left forearm caused a bit of curling of the leading edge so I had to use a small amount of cooling fan (sometimes it helps, even with ABS) to prevent the nozzle from crashing into it. I took the temperature up to 240C this time and was very pleased to discover that this print has absolutely no sign of splitting anywhere.



After a bit of sanding to clean up the support marks I took this series of photos, making the most of the low morning sun - vapour smoothing to follow soon, I hope.












Saturday 22 March 2014

Arch

Pinterest continues to be a great source of inspiration for my 3D printed nude figurines. The latest photo I found was this one, which, according to Google image search, was originally taken by L M Hughes.




It's a fantastic pose and a great challenge for a 3D printer.
I set up the pose using my favourite software and then went through the cleaning process, which is now getting quicker as the routine becomes more established. These are the steps I now go through:

  • Export the model as an OBJ file keeping the body and hair as separate objects
  • Import the model into Blender - the hair and body should be separately selectable 
  • Hide the hair temporarily
  • Select the body and go into point edit mode
  • Pick any vertex and then use Ctrl-L to select all linked vertices. Now press H to hide these points. This is a really easy way to identify any internal components
  • Select all of the eyelashes,teeth, gums and tongue and delete them
  • Keep the front of the eyes but delete the iris, lens and non-visible parts.
  • Use Alt-H to un-hide any hidden vertices
  • From the side view, select all the points in the bottom 1-2 mm of the model and scale to zero on the Z axis - this makes a flat base for the model
  • Now in object mode, hide the body and un-hide the hair
  • Add a high density icosphere mesh so that it surrounds the hair
  • Shrink-wrap the sphere around the hair target using the negative projection setting so that all the points move towards the centre until they meet the hair surface
  • Now delete the hair object and keep the sphere which has taken on the shape of the hair, but in a single closed mesh
  • Un-hide the body and save the body and hair together as an STL file
  • Open the STL file in Cura
  • In the Expert settings, use FixHorrible-Type B - this removes any internal holes and prints much more reliably
  • Turn on the default support settings
  • Use Z-lift on retract to stop the nozzle from catching on edges as it travels from area to area
  • I printed at 0.15 mm resolution with some fairly aggressive cooling from a new fan mounted on the hot-end

Here is the printed model with the support structure still attached.




And here it is with the support removed.



Even the top of the foot came out well thanks to some fairly aggressive cooling.






Monday 13 January 2014

Cicero D'Avila

I have continued in my efforts to make a good print of the sculpture inspired by the Cicero D'Avila pose in my previous post.


Firstly, I remade the arm pose, tipping the woman's head back to improve the angle of the face and prevent the arm support material from falling across it.

 

This smaller version was printed on a delta printer in red PLA and showed that the model was printable although the underside of the arms is still very ragged following removal of the support material.

At this point I decided to change the arm position again, opting for a more vertical configuration that would hopefully avoid the need for any support material. 


Once again I decided to shortcut the process of making the model printable by using Project Miller to re-skin the mesh. Unfortunately, the model still had some errors which resulted in malformed Gcode when I tried to slice it with Slic3r and Kisslicer. This time I found that the new version of Cura (I'm using 13.12) offered some very useful advanced options including Combine Everything (Type B) under the Expert settings. The Gcode looked very good in Repetier Host so I set off the 12 hour print and this time I finally managed to produce a model that does justice to the sculpture I had planned.

Here's a timelapse video made inside the printer using Octoprint.


Some detail shots taken before the smoothing process.







And after smoothing in acetone vapour to remove the print lines and support blemishes.


One more video of the finished product.