Parametric Designs for 3D Print
Designing with Grasshopper can be very challenging when you are new to the application. This week at the Fabricademy we looked into the potential and different use cases of Grasshopper when designing 3D prints.
After following the amazing lectures of Aldo Sollazzo and watching Grasshopper tutorials on Mode Lab’s Youtube channel, I wanted to manipulate the shape of fabric using 3D prints.
Shape manipulation through 3D print on fabric
Dafni Arnellou’s research on fabrics bending thanks to circular shapes printed on the in 3D, fascinated me. Trying to recreate similar results proofed trickier than expected. On some fabrics the PLA wouldn’t stick, other times the height of the print made it to rigrid. 100% cotton knit, didn’t stretch enough, while first tests with Filafex didn’t extrude well.
A dream match for the print was using Filaflex together with a stretchy cotton, polyester blend.
Parametric patterns for shape manipulation
Having found a great material match to alter fabrics, I wanted to go even further and create a parametric pattern, potentially shifting and turning parts of the final garment.
Stretchable pattern designed in Rhino
I designed a triangular line-based pattern that could be tessellated to a 3D print.
Below you see a first print trial in PLA.
The design can be stretched and snaps back into its original shape. If it was applied on garments it would currently adjust to rounded shapes of the body while giving a stiff feeling when moving.
Trying to recreate the design in grasshopper was more difficult than expected. Finding a mathematical formula defining the originally randomly drawn triangular mazes. With the help of o I drew a more rounded spiral version and one that is close to the original idea.
Printed with Filaflex on the same cotton blend as in the earlier tests with circles, the fabric is creasing less when the lines are straight. Even the triangular shapes manipulates the original fabric though, pushing it out. The more rounded designs created hills and valleys on the different sides of the spiral. It could work well for fabric applied to joints like elbows or knees.
Computational self-study on Youtube
Following the instructional videos from Mode Lab I started experimenting with different Grasshopper definitions. I especially got interested in definitions including spirals and attractor points in 2 and 3 dimensional designs.
Dandelion blow design
Out of a radial grid I coded a grasshopper definition with attractor points that tears parts of the grid apart and creates the impression of dandelion seeds being blown away by the wind.
First I created a curve and divided it, connecting its output points with a radial grid. You can adjust the x and y extends of the rid to your liking.
I continued connecting the cell output of the grid to a scale definition using the geometry input. To control the direction in which the elements move I created a point charge including 3 set points and merged their fields.
Similar to the Mode Lab tutorial lesson 7 and 9 I now evaluated the field. Connecting its points input of a hexagonal grid’s Polygon centre E. The strength output of the field evaluator is now lead to a remap numbers and bounds item. For the bounds one I flattened the number input. While the strength output of evaluate field item is now connected to
- value input of remap numbers
- numbers input of bounds
the bounds domain output was also connected the remap numbers as a source. To have an input for the target of the remap numbers item, I constructed a domain with two number inputs.
The clipped and remapped field numbers are now hooked to a graph mapper. Its output was used as the input factor to scale our design.
What is left to do is to find a centre input for the scaling. Here I chose to work with the polygon centre of the hexagonal grid that we used as evaluation points of our field. This way we are tying the size of our field and geometry together.
Using the graph mapper is a very fast and effective way to manipulate the final design.
In the following is a screenshot of the Grasshopper definition from my dandelion design:
Using the same geometry but replacing the attractor points with one spin force and increasing its strength and radius we get a very different result:
It needs a very analytical mind to create complex parametric designs, once you have mastered crafting a logic that shows geometrical designs there is endless variations to explore and play with.
