How to Split Your 3D Printed Site Model
To plan out cities, a lot of inner-city councils these days require 3D-printed site models before allowing a building to be built — and at the required scale, they’re often too big to fit in most 3D-printers. Until the day that most 3D printers can print these large models, we’ll have model splitting.
The question is: Where do I cut?
It depends on a few things individual to each model:
- Size of the 3D printer
- Buildings/structures present
- Terrain present
- Purpose of the model
- Lockability (Ensuring the pieces can’t slide)
The first thing that needs to be considered in the slicing process is the size — you need to maximise the size while still remaining within the dimensions of the 3D printer. Following this, you might cut the model into a grid of pieces that are as big as the printer will take:
Having said that, it’s likely that you’d rather not cut through any buildings present. Instead, following roads (or similar, e.g. rivers, paths, etc.) can be a logical way to split the buildings without impacting the design too drastically:
Cutting through the roads is better, but we can do better still. If the design was cut this way the pieces would be free to slide easily between their spots. When this happens, the model can be frustrating to use as pieces constantly push each other out of the way, given they aren’t glued down. One method that solves this is creating indented edges that lock in pieces more effectively:
Another method that can be used is putting magnets inside the floor of the 3D print and inside each of the removable sections of the 3D print.
These techniques should always be combined for even more secure results.
The last main thing that needs to be considered is what meaning is being conveyed by the different split sections — usually, there will be a main piece that should be centred and not split. Splitting the model into sections that are less likely or more likely overall to be remodeled and then reprinted reduces the amount of time wasted in the future while also reducing 3D print waste.
In the end, these techniques won’t always work for every situation. You’ll have to take your design, and apply the methods you can to achieve the best result. For example, you may want to hide your cuts on the edge of the road, but in order to have the pieces lock in you’ll have to cut across the road every so often, which is better than obvious cuts in the middle but isn’t quite invisible.
Finally, after the lines have been chosen, it’s important to make sure that when the lines are cut they create a 0.5mm gap. If the models are cut without the gap, they won’t fit together flush.
In the next post of this 3D printing series, instead of talking about how to deal with an over-sized print, we’ll be discussing how to deal with overhangs in your models —if you’ve had any experience with 3D printing them you’ll know they can prove to be a challenge to deal with, but not an impossible one!
