As part of the Gr. 8 Cells Science Unit, students usually produce a cell model. This year, students learned how to design and create their cell models using our 3D printer with dual extruders. I started the process by teaching students how to dual extrude by creating a simple cell base and adding a nucleus. Each structure was assigned one of the colours in each extruder. Because some of the organelles or structures are difficult to produce using the 3D design software (e.g. mitochondrion, dendrite), students then learned how to bring their 2D drawing of a cell structure into the software (we use Autodesk’s 123D Design). Their drawn structures were then combined with some of the simpler shapes (e.g. nucleus) which they had previously designed using the software. Below are some of the final cell models and the lesson I used to model the process. As a next step, students will be using these skills in geography to create 3D printed terrain maps.
Creating a 3D neuron: Dendrites are detailed and difficult, so the girls added 2 drawings to their axon, which was designed using the software.
Throughout the research and design process, it was evident that students were developing a deeper understanding of their cell and how it related to their chosen topic as they asked questions and revised their project notes. The final step was a class presentation (which included the function of the cell in body systems and their design process).
Lesson: Turning 2D Drawings into 3D Designs Using Dual Extrusion
Thanks to @LisaJDempster for sharing her steps for single extrusion and Ainslie Martin for the drawings.
Part A: 2D to 3D
1. Imagine the final design. Then deconstruct the design into layers. This example shows 3 layers (students used 2 layers in the cell project). The image needs to be solid fill with black marker on white paper.
2. Convert .jpeg to .svg. Take a picture of each layer (jpg on iphone), save and upload to Online SVG image converter. Settings: I chose monochrome and sharpen.
3. Click “convert file”, save as a download or to your Drive. Repeat for the next layers.
4. Open your design software (Auto123D Design). In the left side (look for the drop down arrow), import SVG as a solid (and scale down) or as a sketch (and extrude). I found it easier to do as a solid, highlight one piece, scale it down to 0.25. Click the remaining pieces and they will do the same. Some students preferred the “sketch” route.
Top Layer: Eyes, Freckles, Moustache
- Export as .stl (left side drop down arrow). If asked to “Combine all objects?” – Yes.
Part B: Dual Extrusion
- Open Makerware (if using a Makerbot dual extruder), Add file (bottom layer). Scale to size – I chose 50%.
- Uncheck the “uniform scale” box. Resize the height by moving the Z axis down (print time becomes longer with increased mm).
- Add the middle, then the top layer.
- Final step – choose the dual extrusion by choosing Object (bottom left icon). Make the bottom and top layer the same colour, middle the alternative. And print!
The Student-Created anchor chart posted in the classroom:
Things to Remember:
- Drawings must be solid black on white paper
- Make sure your picture is just of your drawing (no other markings, desk showing)
- Email drawings as small (not original size)
- Import svg as a solid (not sketch) in 123D Design
- Don’t resize in 123D because it freezes, do it in Makerware
- Don’t forget in 123D to export as stl
Below, Peter and Ryan experiment, using their phones (or mine) to take pictures of their simple designs, which they convert to 3D. This “play time” is an important step before moving into creating a replica of a 3D cell model. Over 70 students with various learning needs from three typical grade 8 classrooms, completed this project either alone or with a partner of their choice.
Cell models, terrain maps, art…. I’m eager to hear other directions you envision this design process being used for in the classroom. Please leave an idea or suggestion.
Postscript: The mother of one of my student’s pulled me aside just before Christmas break, saying she had to thank me for something. She then told me that her son asked for a 3D printer for Christmas (and there are low cost ones out there for this purpose). I didn’t previously consider this student as tech-savy, so my grin was probably bigger than it would have been otherwise:)
Mrs. D's Flight Plan 
