Introduction: Pattern Generation in Grasshopper

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The goal of this project is to create a grasshopper workflow for making a 3D-printable lattice design with holes at certain locations. This is for 3D printing on pre-stretched fabric to create wrinkles. I struggled to do this by calculating intersections with a generated grid, so I decided instead to draw 1 unit cell of my pattern, draw a cutting shape (circle), then use the array function to tile it. Then, I 3D printed one pattern.

Here is the grasshopper file I used in this example.

Supplies

Grasshopper/Rhino

Step 1: Motivation

The motivation for this work is some previous work of mine. I 3D printed some cellular patterns onto pre-stretched jersey, which created these 3D forms when removed from the print-bed. The main drawback here is that I made these manually in Fusion360, which isn't always ideal and takes more processing time. I wanted to automate this process and make it more easy to modify quickly by writing a script in grasshopper. This is still in progress, and I've only done this with one pattern.

Step 2: Draw Unit Cell

This step can be done outside of grasshopper, but my first pattern is a zigzag, so I programmed it in grasshopper so I could easily change the aspect ratio of my zigzag.

I will attach the entire script at the end, but here is the part of my code that generates one unit.

Step 3: Cutting Holes

I used Rdif (region difference for this step). First, I generated the start and end points of each line segment using Endpoints (End) and used those points as the center of each circle. I selected the radius to be slightly larger than the offset distance so the shapes don't touch in the array.

Step 4: Tiling for an Array and Extruding to Make a Solid Object

I used a rectangular array to start, and made a 10x10. Then, I capped it to make the object solid, and converted to a mesh. Then I Baked and exported the file into my slicer for a Print. Due to time constraints, I only Printed a 2x2 array, but pattern generation was the focus. You can also define an array along a curve, or a polar array.

Step 5: Troubleshooting Notes

In the future, I would really like to make these holes using an intersection method. I'll post an update if I can get that working. I was able to calculate intersection points, but I wasn't able to trim the correct parts of the curve.

Here are some of the tutorials I tried (but did not get to work for my geometry):

Here are some of my in-progress scripts in GH.

Step 6: Future Directions

I really want to translate some of my old patterns into this workflow, and use the intersection method to trim the holes. I tried doing this by calculating intersection points and using closed regions, but neither of these worked, even on only 1 unit. I know the best way is python, so I need to learn some python to continue this.