This week we had a 3D printer in the room, so our plans to stencil paint the apple took a back seat until next week. Instead we printed a dice model and then looked at how to build that model.

The printer we used is a Prusa i3 Mk 2.5. To print a model you import it into a program called a slicer which converts it from a polygon based model into instructions for the printer in how to lay down a series of layers of plastic to build the same approximate shape.

The model we printed was a dice. To do this we used ‘hard surface modelling’ techniques, specifically the use of boolean operators. Boolean operators allow you to take two shapes and make a composite shape that is:

1. Difference: The first shape with the second cut-out
2. Union: A shape which is the two shape fused together
3. Intersect: A shape which is only where the two original shapes overlapped

This technique is powerful, but it results in many N-gons (polygons with more than four sides). N-gons are bad in many circumstances. For example severe distortion may result if :

1. If we try to apply smooth shading
2. If we try to apply a subsurface modifier
3. We later try to distort the mesh, as with an animation
4. If we export the model for use in other 3D packages

If none of those apply, hard surface modelling can have its uses.

Here is the instruction video for this week:

The dice model file can be found here.