Chapter 10. Measuring – Tips and Tricks

When designing things for 3D printing in the virtual space it is sometimes easy to forget the relationship they'll have to the real world when printed. And sometimes it is exactly how they'll interact with the real world that is the point of the design, such as when printing an end cap for a pipe or printing a replacement to a broken part. So, it is often very important that accurate measurements must be made when planning and making blueprints.

Part of this blueprint requires a physical object to follow along. Later, when the real world part is complete, a download will be provided so the reader can follow along as in other chapters.

All of the necessary modeling techniques have been covered in previous chapters. This chapter will focus on measuring real life things, and will teach an interesting technique for transferring those measurements to the virtual space easily.

Using a caliper

The most common technique for taking accurate measurements is the use of a tool called a caliper, a must have for anyone who models for 3D printing. Calipers measure distance with a high degree of precision and can measure in three different ways; the outside diameter of an object with the outside jaws, the internal diameter with the inside jaws, or the depth with the depth probe at the far end. The easiest kind of caliper to use is the digital type.

Simply turn on the digital caliper, tare or zero the reading while closed, then open the jaws, put the object to be measured between them, clamp it down, and take the reading. It's fast and relatively accurate without much effort. Most models even have a port that can transfer the measurements directly to the computer. But digital calipers have the disadvantage of being more expensive and relying on batteries which when run out eliminate the ability to measure accurately.

If budget is a concern then perhaps a Vernier caliper is...

Grid paper method

Fortunately, there is a way that a complex shape can be measured accurately no matter how strange the curves or turns. All that is needed is an object to measure, an ink pad, and some centimeter graph paper.

First thing to do is get an object that needs to be modeled for printing. In this example, a drawer guide that has an arm broken off will be used. If it were fixed, this piece should be identical on both sides. This piece has lots of complex shapes and measuring it completely would be a challenge.

A good candidate for the grid paper method is a piece that has at least one flat side, or that can easily be made to have a flat side. The back of this piece is not flat at all, but the front has only two nubs sticking out that would be easy enough to remove. Just note their location before removing them since they'll need to be modeled back in. Then use a sharp blade and cut them off.

Then to be sure that the surface is perfectly flat, use some fine grit sandpaper on a flat...

Summary

This final blueprint explored techniques for modeling 3D objects to fit when 3D printed. Measuring tools such as calipers are valuable aids to any 3D modeler, and using a scanner and ink pad is a clever technique to capture complex objects' shape, provided they have a flat side that can be used like a stamp. The grid paper method is a useful method that works in a surprising number of cases.

Perhaps, one day 3D scanners will be as ubiquitous as their 2D counterparts, but until that day finding ways to transfer real space into the digital space is a problem that will challenge 3D designers. Being creative about making accurate measurement will continue to be a rewarding challenge.

With this last technique, there should be nothing we need for designing objects for 3D printing. Congratulate yourself, you are now a 3D designer. Now the challenges are yours. Find objects that you want to make and model them, if you haven't already started. Find a need and fill it with a plastic object....