Crossword STL model generator

A tool to generate STL models of 3D-printable crossword puzzles.

Prerequisites

• Docker

Usage

Use generate-crossword.sh to convert a CSV file representing a crossword into a 3-dimensional crossword STL.

NB. There are a few caveats so I recommend you read this document all the way through, to understand how to craft the inputs, and what extra steps you may need to take to get your ideal output.

Examples

eg. to generate a model from the sample crossword, with cells the size of scrabble tiles:

./generate-crossword.sh -i samples/clarbert-crossword.csv -p clarbert-crossword -v templates/crossword-default-values-18x20.csv

eg. to generate a simple test with one blank space, one cell, and one highlighted cell:

./generate-crossword.sh -i samples/clarbert-crossword.csv -p test-cells -v templates/crossword-single-cell-test-18x20.csv

In this example, the input crossword is ignored - and replaced by test data.

Test cells	Clarbert crossword

Here's a sample print - using the technique described below to change filament between layers for a multi-coloured effect:

Activity

When running, this tool does the following:

1. Creates working and results directories.
2. Builds and runs a Docker image of ScadGenerator to generate a working SCAD file, using:

• This template: templates/crossword-template.scad
• Input project name: provided in the --project-name / -p parameter
• Input crossword: the file provided in the --input-csv / -i parameter
• Input variables: the file provided in the --input-vars / -v parameter
• Output: working/<project-name>.scad

3. Uses the openscad/openscad Docker image to generate the final STL.

Inputs

Inputs to this tool are CSV-with-caveats. It's not a real CSV reader, so:

• Don't put commas in your strings.
• Don't nest inverted commas.

Input crossword CSV

• Copy the template sheet
• Edit your characters into the crossword tab of the sheet.
  • Use lower case for regular letter grid spaces.
  • Use upper case for highlighted spaces.
  • Leave everything else blank.
  • You may wish to expand the size of the sheet.
  • Export the crossword grid as CSV.

If you have modified anything in the values tab, export that as a separate CSV.

Size limits

You can use a CSV of any size, but of course you'll need to think about what will fit onto your print bed.

For reference, a grid of up to 11 x 9 scrabble sized characters will fit on a Snapmaker 250 series (230mm x 250mm).

During generation, the script will show you the dimensions of the output. Look for echoes of Width and Depth, eg. for the test cells, it shows 65mm x 27mm:

ECHO: "Width: 65"
ECHO: "Depth: 27"

Variable substitutions CSV

To alter variables that control the template, provide an alternative CSV file with the -v option. You can copy templates/crossword-defaults.csv to do this, or modify the values tab of your crossword design spreadsheet. It is a CSV file with no heading and 3 columns:

Variable name, eg. MODE	Value, eg. 0	Human readable notes (not used)

Filament changes

When printing a crossword, there are 3 distinct sections:

• The base
• The cells
• The highlights

To print these in different colours, you'll either need a multi-filament print head, or you'll need to change filament during the print. I'm afraid I don't know much about multi-filament printing.

To change filament during the print, you'll need to incorporate that instruction into the gcode that's sent to the printer. You may be able to do this automatically in your slicer. If not, as with Snapmaker Luban, then you'll need to do it manually by inserting an M600 command in the right place.

M600 (change filament)

To change filament between layers for a multicoloured effect, you'll need an M600 command.

• Identify the topmost printed layer of each section
• Export the gcode from your favourite slicer
• Insert an M600 command at the end of the last layer of each section
• Print from your newly modified GCode directly

See:

• Add command M600 in your GCode file
• M600 Snapmaker gcode reference

Identifying the layers (Luban)

When you've generated gcode, Luban offers an adjustable bar on the right, just by the 'line type' colour key, that shows all the layers.

You can pull it down from the top to hide layers and as you do so it shows an indicator with the number of the topmost layer that's visible. You can use it to see where each section of the print begins and ends, as here:

Base	Cells	Highlights
Layers 0-11	Layers 12-23	Layers 24-30

Therefore to change filament between each section, you'd introduce an M600 at the end of layer 11, and at the end of layer 23.

Example gcode

In this example, we introduce an M600 command right before layer 24 in the gcode file. ... indicates gcode commands before and after the area we're interested in:

...
M600
;TIME_ELAPSED:2507.478646
;LAYER:24
...

As you can see, the layer beginnings are numbered quite clearly, and begin with the prefix: ;LAYER: - this makes it easy to search through large gcode files for the right place to insert your M600.

Printing your altered gcode

Now that you've modified the gcode, you'll need to send it to your printer. Snapmakers will need you to send the file to the printer, and then print it from there using the control panel, rather than initiate a print from Luban.

Roadmap

Planned work:

• Modify ScadGenerator to read and modify the template based on the input CSV.
• Modify the size of the output based on the size of the crossword provided.
• Allow selection of mode.
• Allow the cells to be modified in size, too.