Nature, the brilliant architect, creates surfaces and materials through unique growth processes, whether it is our skin, bird feathers, or tree barks. These are usually basic modules repeated through an underlying geometry, resulting in new structural qualities and functions.
One of the things I find quite intriguing about 3D printing is the possibilities to print new materials that we can then create with. I have seen pictures of 3D printed textile-like materials which I could not find much info on how they were modeled, so I decided to explore some designs here.
With the help of 3d modeling software, in this case Sketchup, we can create models using generative processes like nature does. Although each module is printed with rigid or semi-rigid materials, the new structure takes on the quality of flexible materials such as woven textiles.
Step 1: Design Basics
There are countless geometries that would work. In this instructable the underlying geometry comes from a simple and elegant chain armor structure 4-in-1.
The most basic element, a loop, is repeated so that when a surface is created, each loop is connected to 4 other loops, except for the ones on the edges/ends of the surface.
Since the model is made for 3D printing process, there are unique rules that apply. Really important keys that make the design/ modeling challenging and rewarding-
1. Every loop component needs a minimum thickness to make sure it is strong enough when printed with our choice of materials. I am using 2mm minimum here based on my research, but the model can be scaled according to needs.
2. Although the finished ‘textile’ is a connected flexible web of modules, no module should stick to another in the printing process, which means all points on the surface of one module should have a minimum of 1mm space from that of another!
One little loop and one basic geometry offers infinite creative possibilities. In the next 2 steps we will look at 2 models:
• A variation on the shape of the basic loop module to create heart themed patterns
• A change on the basic module from one loop to two loops, with added embellishments to create dimensional patterns
The animated gifs are created from screen captures of Sketchyphysics simulations. Sketchyphysics is a great plugin (thank you Chris Phillips!!!) which simulates real world gravity, collisions and interactions of physical objects.
Step 2: Hearts
I love the geometric construction process where each step, each new measurement, is grown out of the previous steps/conditions. This is closer to how nature elegantly constructs its creations.
For the hearts 'textile', first we construct 4 octagons with side at 7.2mm and a circle centered on and touching the outer points of the octagons in 2D, this basic geometry layout will give us all the measurements to construct the entire mesh structures. (except for the thickness of the modules which in this case is 3mm, will explain why: it has to do with the difficulty of measuring distances in 3d space)
Draw the first heart by connecting existing dots, see #1, then offset it inside for 3mm, and give it a 3mm thickness.
Next, duplicate it 3 times, move one of them(white) the distance of tip of the heart to the center of the circle in diagram #1, rotate the other(yellow) on plane Y-Z, along axis a 60 degrees.
Last, move the white module along Z axis 7.2mm(the sides of a octagon), move the yellow module along X axis the distance of the circle's radius, the up Z axis 2x7.2=14.4mm. Duplicate, move it the relative distance between a corresponding point on the white and pink module.
Now we have the basic distances for all the repetitions. Sketchup has this great tool to duplicate components in space with a couple of clicks, no labor intensive stringing here!
Now a little about why the 3mm: We had intended the test pieces to be 2mm to start. It's important to have at least 1mm space between modules so they won't stick in the printing process. So if we create each module to be 3mm thick, and check to make sure no modules are touching when the mesh is finished, then offset the module back 0.5mm all around, then we can be sure about the 1mm clearance. This is so much easier than trying to measure random points in space!
Yes I discovered this trick the hard way! =)
Step 3: Waves
This variation is generated through the use of Vesica Pisces. Volumes have been written about it. In the mystical tradition, it is regarded as containing the principles of all creations. It is also used as proportioning system in sacred architecture throughout history.
Start with one circle, in this case 20mm diameter, with a 3mm offset inside.
Duplicate and move the second circle from the outer edge to the very center. The intersection between the 2 circles(ignore the offset for now) is the Vesica Pisces.
The length of this Vesica Pisces a-b give us the diameter of the 3rd circle(blue). Rotate it at center along X axis 90 degrees, move 10mm(radius or original circle) plus 3mm(thickness) along X axis. The move the first 2 modules(white&green) in opposite direction along Y axis 3mm each.
Now we have the very basic component- The white and blue rings. The green ring gives us the reference to duplicate along Y and Z space. If we mirror the white ring using the center of blue ring along X axis, it will give us the relative distances to duplicate each module along X.
Because it is possible to 3D print with more than one materials in a model, it can be fun to add embellishments of different materials(colors), which will result in new surface patterns and designs! Just make sure of that 1mm minimum clearance between modules!
Step 4: Convert and Export SketchUp Files to STL for 3D Printing
Sketchup is a “polygonal surface modeling” program, which means that curves are approximated using many flat faces - the default circle in Sketchup has 24 sides. The more faces a curve is made of, the smoother it becomes. A good tip is to increase the number of segments so each individual segment is about 1/32” (1mm) long.
The size of every part in a model needs to work with the printer's material specifications and limitations. The thickness you need will vary depending on the material you are printing in. For example, some plastics require a wall thickness of 1 mm, while 3D printed ceramics require a minimum of 3 mm.
There are very helpful guidelines such as these-
Here’s the plugin I used to convert Sketchup file to STL.
After you have installed the plugin, reopen SketchUp and select the object to be 3D printed, click on the drop down menu for “TOOLS” and select “EXPORT TO STL”. That's it.
The 2 files I included here are the basic structures used in step 1 and 2. Each component measures about 2mm thick.
Step 5: Creative Possibilities
Now that we have created our materials, maybe we can make some fun stuff, how about beachwear!
As I was playing with the forms of embellishments, an idea came to make them with added 3 dimensional volumes instead of just flat discs.
Like fabrics, these 3D textiles can be cut into all kinds of shapes and joined together with many materials to create exciting pieces of art, fashion, accessories, and much more.
3d printing services offer many choices of materials to print with. Right now I am considering semi-flexible materials, and will post update in the future.
Step 6: Resources, Etc
As a total beginner in 3D printing, I found lots of tutorials here very helpful, topics ranging from modeling for 3D printing, to materials and design guidelines -
If you are interested in Sketchyphysics, here are a couple of good places to start-
I must thank our amazing instrutables community for introducing me to the wonderful world of 3D printing, and for the fabulous instructable that Mario wrote(thank you mario!!) https://www.instructables.com/id/Beginners-Guide-to-3D-Printing-with-the-Objet-Con/ which taught me a great deal in such a fun and exciting way!
As with all technology, 3D printing will become more precise with more materials to print with. Imagine what we could do on a microscopic level? Perhaps one day we will be printing materials like trees- that store water, breathe life, and rustle in the wind.
(The inspiring peacock feathers-Photograph by Lorenzo Cassina, National Geographics)