The outline of the top pattern inside the base. What the hell is that Prusa Slicer doing?
 
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The outline of the top pattern inside the base. What the hell is that Prusa Slicer doing?  

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Anton Mymrikov
(@anton-mymrikov)
Member
The outline of the top pattern inside the base. What the hell is that Prusa Slicer doing?

Can someone explain how to avoid this and why it is still not fixed by the developers?

For example, I am printing a medallion or keychain, which is a disk with some kind of drawing on the surface, let it be Mickey Mouse. The picture is not embedded in the disk, it is strictly positioned on top of it. The disk is set with 100% infill.

By simple logic, the printer should print a flat disk and only then start to form a drawing on its surface. But by some strange logic it starts printing the contours of this drawing in the middle of the disk. First it fills the layer around this drawing, then it fills this drawing. The same story if the disk is not 100% filled.

All would be nothing, but at high speeds, especially at not 100% filling, individual strands at sharp movements begin to rise, the nozzle touches them, the residue of the filament remains on the nozzle, burned and then in the most unpleasant place, by the law of meanness in the last layer, stick into the plastic and spoil the whole model. This is especially true for white color. Customers do not like dirty brown spots on white models.Because of this, I have a constant 7-8% reject rate.

What should I do with this damn slicer so that it doesn't draw a drawing inside the disk?

I know Sweet Cheese's solution, but it is very cumbersome, especially for complex models.

Thanks.

Napsal : 11/12/2024 5:02 am
Brian
(@brian-12)
Reputable Member
RE: The outline of the top pattern inside the base. What the hell is that Prusa Slicer doing?

Make it multiple parts.  Take your model in Prusa slicer or CAD and cut the object into parts.  (You can look up on YouTube how to do this in PS, it's really easy) This will keep the orientation to one another but allow you to apply different properties to each part. 

Also the slicer is doing exactly what you tell it, there is nothing wrong with it. Based on the number of bottom and top layers etc. its creating the geometry based on settings you give it 

If you want a more detailed analysis upload a zipped 3mf of your file in question and we can look it over.

 

Napsal : 11/12/2024 6:39 am
Neophyl se líbí
Anton Mymrikov
(@anton-mymrikov)
Member
Topic starter answered:
RE: The outline of the top pattern inside the base. What the hell is that Prusa Slicer doing?

Hi Brian,

My model is originally partitioned and composed in the slicer as one two-part object.

What's the point of posting my model if you can reproduce it with two cylinders in the slicer. Take one cylinder 10mm high and 50mm diameter and add to it as a part a second cylinder 5mm high and 30mm diameter, positioning it in Z at a height of 10mm so that it is on top of the larger cylinder, set 100% infill for both cylinders, do the slicing and look at the top layers of the larger cylinder.

I understand this is a slicer error that no one will fix, not a deep philosophy about geometry. And there is no simple solution.

I guess I have to look for or buy a normal slicer, instead of Prusa Slicer.

Napsal : 11/12/2024 7:00 pm
Diem
 Diem
(@diem)
Illustrious Member
RE: The outline of the top pattern inside the base. What the hell is that Prusa Slicer doing?

Can someone explain how to avoid this and why it is still not fixed by the developers?

It *is* fixed - slicer is calculating external perimeters according to the external geometry.  If you want exterior perimeters internally insert a thin void where you want them.  This is of most use for placing internal reinforcement where directted stresses are expected.

What's the point of posting my model if you can reproduce it with two cylinders in the slicer.

Because in many cases the issue is not where the user thinks it is (or she would have fixed it) or it is an interaction between geometry and settings.

The disk is set with 100% infill.

100 fill is almost always a mistake; it adds little strength, makes catastrophic (ie. shattering) mechanical failure more likely because there are no crack stoppers and leaves the slicer no room to accommodate adjustments.

at high speeds, especially at not 100% filling, individual strands at sharp movements begin to rise,

High speed is always traded off against quality, slow down.  The strands rise because you have left the slicer no room to accommodate adjustments.

Customers do not like dirty brown spots on white models.

So print brown models and, if required, paint them white.

White filaments are always trickier to print as they contain so much pigment that their deposition flow becomes non newtonian.

I guess I have to look for or buy a normal slicer, instead of Prusa Slicer.

If you go back to early slicers from about 2010 - 2012 you will find this behaviour.

Cheerio,

Napsal : 12/12/2024 9:50 am
Anton Mymrikov se líbí
Brian
(@brian-12)
Reputable Member
RE:

 

Posted by: @anton-mymrikov

Hi Brian,

My model is originally partitioned and composed in the slicer as one two-part object.

What's the point of posting my model if you can reproduce it with two cylinders in the slicer. Take one cylinder 10mm high and 50mm diameter and add to it as a part a second cylinder 5mm high and 30mm diameter, positioning it in Z at a height of 10mm so that it is on top of the larger cylinder, set 100% infill for both cylinders, do the slicing and look at the top layers of the larger cylinder.

I understand this is a slicer error that no one will fix, not a deep philosophy about geometry. And there is no simple solution.

I guess I have to look for or buy a normal slicer, instead of Prusa Slicer.

I find it offensive that were trying to help you and your effectively being combative.  Why bother to ask questions on a forum if you don't want help?

Still no slicer error, user error. I created your example.  If you select the interface shells option in the multiple extruder tab and then change any property about the 2nd part it'll do what you ask.  If you leave all properties of both parts exactly the same PS considers them a single part and generates the top and bottom layers as you've specified as a single part.  This is because you've not made anything different about your 2 parts, effectively defeating the purpose of having parts to begin with.

You could probably produce a similar result by altering the number of top and bottom layers, but without seeing your model, like I asked, I'm not sure.

 

Napsal : 12/12/2024 12:57 pm
Anton Mymrikov se líbí
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