Improving Print Quality

Note - This guide is in beta. Please provide feedback, whether it is positive, negative, or neutral. Your feedback will help me make this page better! Photos will be included in a future version, but for now all you get is a wall of text :)

Octolapse was built with print quality in mind, and offers tons of features for doing just this. The default settings, however, are geared towards compatibility, and require some understanding in order to optimize the quality for your particular printer and gcode file. This guide contains some basic and advanced steps you can take to get the best possible quality with Octolapse.

Real-Time Gcode Processing - A Primer

Octolapse's basic job is to determine when to take a snapshot, and how to move the X, Y, and Z axes and extruder to and from the snapshot position. That means Octolapse has to deal with retraction/detraction, z-lift, and axis speeds. It also must to accurately track the printer's exact position and extruder state as well as a host of other details. Since Octolapse processes GCodes in real time, it needs some knowledge about your slicer settings in order to accomplish this.

Step 1 - Match your slicer settings

The MOST important quality consideration for Octolapse is to enter your slicer settings for the gcode file you are printing. If you change your slicer settings, you should also update Octolapse's printer profile, otherwise your quality may suffer. The first thing to do if you are concerned with quality is to review your printer profile settings.

Here are the settings in order of importance, all found within the Printer Profile:

1. Retract Length - Incorrect values here can lead to stringing, and/or zits/blobs on your print.
2. Z-Hop Height - Without this value Octolapse will not lift properly, and similarly will not know when your printer is lifted
3. Retraction/Detraction Speed - Octolapse must know how fast to retract and detract. Incorrect values will lead to stringing/oozing or other problems.
4. Z Movement Speed - Octolapse must understand how fast to lift to prevent artifacts from being formed during a lift and retract operation.
5. Movement Speed (Travel) - The less time Octolapse spends taking a snapshot, the better your print quality will be. However, traveling too fast can lead to some mechanical issues, and could possibly damage your printer.

Step 2: Moving on from the Layer Trigger

Octolapse detects layer changes by looking for an extrusion that is greater than the previous highest extrusion. For this reason, the default layer trigger tend to take snapshots just before or after the first line of plastic goes down on a new layer. If you are printing the external layers first, this can lead to some artifacts on the outside of the print.

The snapshot profiles control both 'when' and the 'how' of the snapshot routine. If Octolapse is taking pictures on the outside surface of your print, you WILL notice this. However, the default 'layer' profile tends to do just that. It is also the simplest and easiest profile to use and understand, which is why it's the default profile. Defaults values are rarely optimal values, and Octolapse is no exception.

If your print profile settings all match your slicer, you can utilize some advanced features to dramatically reduce features and artifacts. Let's take a look a few other options and how they can be used to improve your print quality:

1. Try a 'ZHop & Retract Only' profile - These profiles are configured so that snapshots will only be taken when your printer is lifted and fully retracted. Your slicer will be pretty good at determining where to lift and retract without causing quality issues (it does generate the gcode afterall). Your z-hop height AND retraction length settings MUST match your slicer for this to work. Some prints may not have lift and retract on some layers and may have none at all. In this case Octolapse would not take any snapshots. Many slicers have a settings to lift and retract at the end of each layer, which would ensure that a snapshot is taken every layer no matter what.
2. Use a Height Trigger - Taking fewer snapshots leads to fewer travels, which improves print quality. It will also speed up your print a bit! If you are printing something quite tall, you might not need a snapshot on each layer. With the height trigger you can tell Octolapse to only trigger only once every height interval. For example, if you are printing at a 0.2MM layer height and you use a Height trigger set to 0.4MM, Octolapse will take a snapshot every other layer. If you change the height to 0.3MM, Octolapse would take a snapshot 2 out of 3 layers.
3. Use a GCode Trigger - This trigger gives you 100% control over exactly when a snapshot is taken. Generally, I recommend adding the following Pseudo-GCode to your 'after layer change' script:

Snap

Make sure you enter the gcode exactly, and do not comment it out. It's fine to add a comment to the end of the line like so:

Snap ; take a snapshot

Step 3 - Position Restrictions

These can be found in the 'Advanced Snapshot Trigger Options' at the very bottom of the snapshot profile. This setting has been buried somewhat because it takes a bit of skill and understanding to use.

Here you can define regions where snapshots are allowed, and where they are not. These regions can be rectangular or circular. You can either 'Forbid' Octolapse from taking a snapshot within a region or you can 'Require' Octolapse to be in a region before taking a snapshot. You can add as many regions as you wish. For example, You could restrict snapshots to infill, or only over a waste tower. There's even an option to 'calculate intersections' which allows Octolapse to take a snapshot even in the middle of an extrusion command. Using many regions or using the 'calculate intersections' option takes a bit more processing power, so don't try this on a Pi Zero.

Step 4 - Advanced Trigger Extruder State Requirements

Within the Snapshot Profiles there are some advanced settings available under each trigger type. If your print profile settings are correct, Octolapse can track the state of your extruder. For example, it knows if your printer is about to retract, is in the middle of a wipe, or is currently extruding. The default layer profile is geared towards compatibility, allowing snapshots at the beginning of and during extrusion, but forbids snapshots on detraction and when only partially retracted (middle of a wipe).

You might notice that the 'ZHop & Retract Only' profiles ONLY allow snapshots when the extruder is fully retracted. This is the ideal situation, since Octolapse doesn't have to retract or detract at all!

If you are TOO restrictive, Octolapse may not take any snapshots or may miss taking snapshots on some layers. If you are too permissive, your print quality will suffer.

Lift and Retract

These two options tell Octolapse to lift and retract before each move. It ONLY does this when necessary and will not lift or retract more than is defined in your printer profile. It's recommended that you leave these two settings enabled, though there are some special situations.