Lesson 6: Practical 3dm Commands and Text Embossing

Estimated time: 60-90 minutes

Learning Objectives

• Master key 3dMake commands: 3dm describe, 3dm preview, 3dm orient, 3dm slice¹
• Apply text embossing and parametric customization to create a personalized keycap²
• Generate tactile 2D previews for accessible model inspection¹

Materials

• 3dMake project scaffold with src/main.scad
• Access to a slicer (PrusaSlicer, Cura, or Bambu Studio)
• Optional: printer for test print
• Reference: 3dmake-setup-guide.md for command reference

Related Project: See cube_keycap.scad for a worked example combining text embossing and the 3dm commands.

Understanding the 3dm Command Suite

The 3dMake CLI provides a systematic workflow for model management. Each command serves a specific phase of the design-to-print pipeline.

Step-by-step Tasks

1. Create a parametric keycap model with top-level parameters for customization²:

   // Cube Keycap - Parametric Design
   // A customizable keycap with embossed text
   
   // Parameters (easy customization)
   key_size = 18;      // mm - width/depth of keycap
   key_height = 12;    // mm - height
   wall = 1.2;         // mm - wall thickness
   letter = "A";       // Character to emboss
   letter_size = 10;   // mm - text height
   letter_raise = 0.8; // mm - emboss depth
   
   // Hollow shell
   module shell(){
     difference(){
       cube([key_size, key_size, key_height], center=false);
       translate([wall, wall, wall])
         cube([key_size-2*wall, key_size-2*wall, key_height], center=false);
     }
   }
   
   // Text embossing on top face
   module emboss(){
     translate([key_size/2, key_size/2, key_height-0.01])
       linear_extrude(height=letter_raise)
         text(letter, size=letter_size, halign="center", valign="center");
   }
   
   // Assemble keycap
   union(){
     shell();
     emboss();
   }
   

2. Run 3dm describe to generate a text-based analysis of your model:

   3dm describe src/main.scad
   

   This will output a description suitable for non-visual inspection. If AI is configured, you’ll also receive suggestions about geometry and potential print issues.

3. Generate a tactile 2D preview with 3dm preview:

   3dm preview src/main.scad
   

   This creates a simplified 2D outline that can be printed for physical inspection or converted to braille for accessibility.

4. Analyze print orientation with 3dm orient:

   3dm orient src/main.scad
   

   This command suggests the optimal orientation for printing-minimizing support material and maximizing surface quality.

5. Prepare for printing by slicing your model:

   3dm slice src/main.scad
   

   This generates G-code (build/main.gcode) ready for your printer.

Checkpoint

• After task 1, you have a working keycap model with parameters
• After task 3, you have a 2D tactile preview in build/
• After task 5, you have G-code ready to send to a printer

Customization Challenge

Modify the keycap by changing these parameters and observing the results:

Quiz - Lesson 3dMake.6 (10 questions)

1. What does 3dm describe provide that 3dm preview does not¹?
2. Why is 3dm preview useful for accessibility¹?
3. What does 3dm orient help you determine about your model¹?
4. How does parametric design (using variables) make customization easier²?
5. Name one use case for embossed text in a 3D model².
6. True or False: You must run 3dm build before running 3dm describe.
7. Explain the relationship between wall thickness and print strength.
8. Describe what happens when you change the $fn parameter in your text() function.
9. How would you modify the keycap code to add a second embossed character²?
10. What information would you include in a 3dm describe output for a manufacturer¹?

Extension Problems (10)

1. Create three keycap variants (small, medium, large) by changing key_size and export each as a separate STL².
2. Add a decorative border using linear_extrude and text(); verify the result with 3dm preview¹.
3. Run 3dm describe, 3dm preview, and 3dm orient on your keycap; document all outputs¹.
4. Modify the emboss module to support multiple characters in different positions².
5. Create a parametric keycap library with variants for different keyboard layouts (cherry, OEM, DSA profiles)².
6. Design an accessibility assessment: use 3dm describe and 3dm preview to validate your model for non-visual users.
7. Build a custom keycap design system: parameterize profile, height, wall thickness, and emboss content; generate a product family.
8. Create a comparison study: test three different emboss depths and document print quality differences.
9. Develop a keycap troubleshooting guide: common failures (emboss erosion, wall cracking, text illegibility) and solutions.
10. Write a comprehensive keycap design documentation: parameters, materials, print settings, post-processing, and accessibility features.

References

1. 3DMake GitHub Repository - https://github.com/tdeck/3dmake ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8

2. OpenSCAD Manual - Text & Linear Extrude - https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Text ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8