If it fits, it fits.
Designing a container for an object is not difficult. Take any shape―a rectangle or a circle―and extrude it. A non-specific container for a non-specific object―a deck of cards, a pair of pliers, grandpa’s false teeth. Easy.
The challenge is specificity. Designing a vacuum-formed container meant to keep a collectible action figure safe during shipping and at the end of the voyage showcase its contents on a store shelf, this requires thought. A specific container, for a specific payload, for a specific set of conditions―not so easy.
Picture that action figure and its box. You’re tasked with designing a fixture―the clear plastic tray to hold the toy in place inside the box. That tray would need a cavity in the shape of the toy―though not exactly. While it needs to follow the contours of the toy in places, it should be loose in others to allow for easy placement and removal of said toy. Simply subtracting the toy’s shape from the tray’s shape won’t do.
Sculpting specificity
A sample of the object is often sacrificed in the making its own of form-fitting packaging. It serves as the starting point, the base shape. Material is added to it, usually plaster, clay or another modelling compound, morphing its contours little by little. Certain sections are smoothed over; voids and overhangs are filled. The goal is to find a composite shape that balances equivalence to the original shape, package architecture and manufacturability through vacuum-forming. Arriving at such a shape is both art and science.
It’s such slow-going work that even a fully digital workflow leveraging software and 3D printing confers no time advantage. But what if the process could be broken down to discrete steps and then automated? It’s a thought that I keep returning to every time I do this kind of work.
Then in early 2025 I hunkered down and began research into procedural methods for generating form-specific tool geometry. The effort eventually led to the development of the algorithm I call Drafter, the engine under the hood of Blister Magic.
An algorithm.
Drafter requires three basic inputs: a base 3D model, a ground plane, and a draft angle. First, every face of the base model is analyzed for orientation relative to the defined ground plane. Then, any face that is angled less than the draft angle is discarded. The remaining surfaces are then patched up with new faces, each one set up at a specific angle, the draft angle. After some post-processing, the results is a water-tight, void-free, ‘drafted’ version of the input model.
It’s one thing to dream up a procedure that could accomplish the above in theory, and quite another to see the Python script I’ve been sketching for weeks finally looping through, error-free, and seeing its output on screen. What took hours, henceforth, takes seconds. The idea works.
Going from proof-of-concept to desktop application was a journey unto itself. After months of working in secret I’m happy to finally share my little project with you. Blister Magic is meant to simplify that deceptively simple task of making contour-matched geometry with precisely sloped side walls, a trick that needs to be pulled on a regular basis in the design of packaging, jigs and fixtures, molds, or even medical prosthetics.
Hope you give Blister Magic a try and pull a fast one soon. Enjoy! –JT
Drop me a line at hello@blistermagic.io and let me know how you plan to use Blister Magic.