Any but the simplest designs require expertise with computer-aided design (CAD) applications, and even for the experts, the design process is immensely time consuming.
Researchers at Massachusetts Institute of Technology (MIT) and the Interdisciplinary Centre Herzliya in Israel aim to change that, with a new system that automatically turns CAD files into visual models that users can modify in real time.
Once the design meets the user's specifications, they hit the print button to send it to a 3D printer.
"We envision a world where everything you buy can potentially be customised, and technologies such as 3D printing promise that might be cost-effective," said Masha Shugrina, an MIT graduate student in computer science and engineering and one of the new system's designers.
For a CAD user, modifying a design means changing numerical values in input fields and then waiting for at least a minute while the programme recalculates the geometry of the associated object.
Once the design is finalised, it has to be tested using simulation software. Those tests can take anywhere from several minutes to several hours, and they need to be rerun every time the design changes.
The new system, called Fab Forms, begins with a design created by a seasoned CAD user.
It then sweeps through a wide range of values for the design's parameters - the numbers that a CAD user would typically change by hand - calculating the resulting geometries and storing them in a database.
For each of those geometries, the system also runs a battery of tests, specified by the designer, and it again stores the results.
The whole process would take hundreds of hours on a single computer, but in their experiments, the researchers distributed the tasks among servers in the cloud.
The researchers used eight designs, including a high-heeled shoe, a chess set, a toy car, and a coffee mug. The system samples enough values of the design parameters to offer a good approximation of all the available options.
The researchers also developed some clever techniques to exploit similarities in design variations to compress the data, with the largest model taking up to 17GB.
Finally, the system generates a user interface, a webpage that can be opened in an ordinary browser.
The system automatically weeds out all the parameter values that lead to unprintable or unstable designs, so the sliders are restricted to valid designs.
However, if a particularly sharp-eyed user wanted a value for a parameter that fell between two of the samples stored in the database, the system can call up the CAD programme, calculate the associated geometry, and then run tests on it.