I am trying to print cat head like on pic 1 when I am slicing is filling bottom layers and some walls are getting missing. When I press repair model is coming like on pic 3, which is not correct either. Is it file issue or slicer? I want it printed like on pic 1.
Non-manifold edges are a CAD problem, not a slicer problem. Your model file is defective. However, that doesn’t mean it won’t slice or print.
Scale up the object. Do the walls reappear when sliced? If so, turn on “detect thin walls” in the slicer (Arachne) and see if that fixes your problem.
If scaling the object doesn’t correct the problem, the issue is more fundamental and you will need CAD to correct.
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I found that scaling (resizing to smaller or larger) from original size appeared to be a cause of this issue also. could this be the issue ?
The model file should scale uniformly, so all the vertices in the model should stay aligned with each other as the model is scaled. So no, scaling should not be able to cause this problem.
Are you saying if you reload the original STL the slicer does not say that there are non-manifold edges until you attempt to scale it?
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Scaling changes the model structure hence why two lines appear together on the same layer, that is my understanding, especially when making the model smaller
and one you appear to agree with .
that is my understanding
I’m afraid your understanding could not be more wrong. Scaling does not make any changes to the model structure. It’s called “uniform scaling” for a reason. 
When you scale, everything moves by the same amount, so everything stays in the exact same place relative to everything else.
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First repair the model in the Bambu slicer. The object may consist of several meshes that overlap, which could be the reason for the errors.
If it does not work at all, you may have to create a new mesh from your existing one. This is possible with some software. There is also software that recalculates a 3D object according to a given resolution, which makes the file much larger (because many more surfaces are created), but it can then be simplified again in the Bambu slicer. A similar possibility in another way would be to first print the object as a whole and then digitise it again using a 3D scanning process. Then you only get an outer shell, which you can then easily cut/split.
Best regards!
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you didn’t check vase mode accidentally by any chance did you. Only time I’ve see something similar
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I understand what uniform scaling is, i also understand that as a mesh becomes smaller vertices need to merge into one, be it a vertices or layer, because it has nowhere else to go, id of thought even more so with layers being as small as 0.2mm
This statement:
I understand what uniform scaling is,
directly contradicts this statement:
i also understand that as a mesh becomes smaller vertices need to merge into one,
As a mesh is scaled smaller, all the vertices in the model retain their exact same relationship to each other. The “ratio” between the positions of any two vertices in the model will not change. Everything scales uniformly. If it did what you are saying, that would not be uniform scaling. It wouldn’t be scaling at all. It would be “squishing” which is not the same thing at all .
To the limits of precision of the computer system doing the math, no matter how big or small you scale your print, it will maintain the exact same shape it originally had. Nothing merges in to anything. A model that is manifold at its original size will be manifold at any other size it is scaled to, provided the scaling is “uniform”.
Layer height has nothing to do with scaling. It’s an “independent variable” determined by the slicer’s settings. It is not driven by the geometry of the model. 0.2mm layer height on a 5mm square cube is exactly the same as 0.2mm layer height on a 250mm square cube.
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Is the head hollow perhaps? if so then scaling smaller will thin the walls to the point that they are unprintable. A quick check would be to load the original model, scale up as big as your build plate, then slice it and move the vertical slider down to see if it’s hollow.
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Potentially could be as slicer is asking for scaling item due to inc / mm issue I believe. It is a hollow item. I will try your suggestions once back from work and will update. Thank you
What does restructure in mean?
verb (used with object),re·struc·tured, re·struc·tur·ing. to change, alter, or restore the structure of
layer height is a pre determined setting fixed for the slicer to generate gcode for.(layer at a time
Non-manifold geometry refers to any edge that is shared by more than two faces. This situation typically arises when a face or edge is extruded but remains in its original position, resulting in two identical edges directly overlapping each other
One of the simplest ways to fix non-manifold edges is to delete the faces that create them, something i believe the windows service that BS uses does to fix a mesh.
The technical definition of “manifold” in the context of 3D printing (it has multiple meanings in other contexts) is “a collection of points forming a set, where the set forms a topologically closed surface in three or more dimensions”.
Consider two cubes sharing a common edge. It’s a single object with one spot (the shared edge) with zero thickness. Technically, this is non-manifold. It cannot be repaired by deleting any faces. The slicer will probably slice it just fine, though.
Consider two adjoining faces that share common vertices for the end points of their common edge. But one of the edges has an additional third vertex. These faces are non-manifold. They cannot be repaired by deleting a face, either. The slicer may or may not successfully slice this type of error.
A stray face, a polygon that is not part of a surface that fully encloses an interior space (=“watertight” or manifold)) is non-manifold. It can be fixed by deleting it (but the slicer will implicitly ignore it because it has no thickness). But this is rarely the type of non-manifold error that occurs in 3D modeling. The more common type is the extra/misaligned vertices problem. Which can be very tricky to repair.
And irrespective of the definition, you cannot get a non-manifold model starting from a manifold model and doing nothing more than scaling. Up, down, gigantic or microscopic, the relationship of the vertices to each other in the model does not change as a result of scaling.
I think the slicer uses a license from a company called NetFabb to do the mesh repair. The slicer from Formlabs that I use for my SLA printer uses this service. And I’ve got a stand-alone version in my toolbox for mesh analysis repair.
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I’ve had this problem before. Due to the fact that it is uniform scaling the walls become too thin when scaling something down. I had to load the model in Blender and use the solidify modifier to increase the thickness of the walls so that when scaled down to the size I wanted the walls were still thick enough for my .4 mm nozzle to print.
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