This week I added real time remaining estimates to matterQ. A problem I’ve had for a while is having no real idea of how long a print is going to take to complete. Slicers like Cura give an estimated print time but this is often wildly inaccurate when actually printing.

Part of the problem is the way firmwares like Marlin will interpret gcode loosely suggestively rather than literally so the slicer has little idea about how long a set of instructions will actually take to execute. With my Ultimaker 1 running Marlin I often get time estimates from Cura that are less than half the time it actually takes to print.

In matterQ I have taken a very different approach to time estimates. When the job starts the current time is recorded. As matterQ already tracks filament extruded at each line of gcode we can look at how long it has really taken to print all of the filament so far at any point in the print. We don’t try to calculate print time from the gcode, we just measure real print time and extrapolate.

In many OpenSCAD designs I have needed to work out some trigonometry and convert this into a series of translate() and rotate() functions for each component of the design. This is somewhat tedious and makes for some rather unreadable code.

In computer game programming spherical coordinates are particularly popular as they make lots of the calculations easier to understand. Since I started using spherical coordinates in OpenSCAD they have become my de-facto solution for a lot of cases.

Use the spherical_translate() as you would translate() but instead of passing an array of [x, y, z] pass an array of [radius, inclination, azimuth].

Here is the spherical_translate() module and an example:

The first component of Cede finished. Read more on the Cede blog.

This is the first box made on the new dovetail jig! It takes a while to get it set up just right but after that it is pretty quick to cut whole lengths of lapped dovetail.

For the best 3D printing results the “steps per e” should be calibrated for each different filament.

PlasticDB makes that an easier task. Open the full post to see the code. Updates will be published on the same gist.

Works best with matterQ.