Cutting Into 21 Pieces

Bambu Lab P Series Troubleshooting
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I have a model I want to split into (7 x 3) 9" x 9" tiles.This is a combination of 5 different-sized pieces together making a rectangle.

The rectangle file is much larger than the bed dimensions. Should I shrink it to fit the bed, then cut it up, or cut it in its original size? Is any detail lost if I shrink it to fit the bed, and so I should cut it in its large original form?

This has 3.5 million manifold errors. Should I run the fix on each individual plate so it doesn’t take a month to fix, or do it all at once. I guess I could simplify the model.

Thanks

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  1. manifold errors: Most apps that will help you cut up a model will not accept the task until it is manifold. Would recommend repairing the base file.

  2. Slicers will help you add attachment/alignment features on the cut, so I’d start there. Beware, when you have the task done, SAVE YOUR 3MF, and potentially re-export all the pieces as stls for your future usage. You will never be able to reproduce it and “reprint piece 7 that warped” if you do not do these steps lol

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No detail is lost when you scale a model. Every vertex moves by the same percentage relative to the center of the object. You lose resolution when you print it, though, because the nozzle doesn’t get smaller even though all the features do…

And yeah, you need to fix your Non-Manifold errors. If you do anything besides simple scaling and moving, non-manifold edges can lead to chaos.

With that many errors, I would guess that the model file might simply need the vertices merged (meaning polygons that have a vertex that aligns with another use separately defined vertices instead of actually sharing the one, so geometrically they’re not connected even though there is no actual geometry error). 3.5M is a lot, but it may not take as long as you think…

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Splitting a model, while possible in a slicer, should always be done within the CAD program used to create the file.
The geometry of a model is often too complex to allow for straight and perfect cuts, especially if these intersect the geometry in bad places

Let me try to make a useless point here…
The slicer works with a simplified model on a layer base.
All model related operations however would have to happen on a CAD level.
Take a ‘simple’ sphere.
In the cad program it is created using rings of different diameters while triangles fill the void between them to form the face.
No problem at all cutting this right along one of these rings, but at any different angle it creates a huge mess.
The slicer can only do most basic operations and they all struggle with cutting existing geometry lines in a matching fashion - hence the resulting manifold errors.
Cutting a model means also making a new face, which can be impossible for a straight cut if the ‘edges’ are all over the place.

A thing that seems to work in similar ways in most slicer than how it works in CAD is not to split a model at all.
A total pain in a slicer but it goes a bit like this:
Import your part and have it intersect with a plain and straight solid.
Remove all but the single part not covered by the solid and repeat in the same way until you have all parts for the model ‘split’ this way.
What’s the difference?
Trimming a model with a larger solid usually results in the slicer knowing that there is a matching flat face.
While there might still be manifold errors they should be reduced to the point where a repair actually works without ruining the model.

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