PrusaSlicer automatically scales down 3D model to approximately 1/50th of design size.
 

PrusaSlicer automatically scales down 3D model to approximately 1/50th of design size.  

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dz-1
 dz-1
(@dz-1)
New Member

I have successfully printed over a dozen prints with my i3 MK3. CAD software is Solidworks. I re-created model in metric and imperial but I am getting the same result. In the attached pic it shows the size that PrusaSlicer is transforming my model into. Consider that the design size for this simple flange bushing is a 3 inch diameter x 2 inches long. Why is this happening to the STL file? Please advise. thank you[caption id="attachment_15040" align="alignnone" width="600"] Flange bushing shown in PrusaSlicer preview[/caption]

Posted : 19/02/2020 2:32 pm
joan.t
(@joantabb)
Veteran Member Moderator

Did you use imperial units or metric units when designing the model?

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 19/02/2020 6:53 pm
joan.t
(@joantabb)
Veteran Member Moderator

Slicers usually use metric measurements. 

If you use imperial units without scaling. The models end up tiny

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 19/02/2020 6:56 pm
dz-1
 dz-1
(@dz-1)
New Member

I re-created models in both metric and imperial but I had the same result. I did figure out a fix...

I changed the scale factor in PrusaSlicer to 2540% (1 inch = 25.4mm) and it worked fine. What i found strange is other models were scaled perfectly when designed in imperial units but this particular model was a brat.

Posted : 19/02/2020 7:09 pm
joan.t
(@joantabb)
Veteran Member Moderator

2540 is the scaking factor from inches to metric ...

Chances are the original file was exported in imperial units

 

Regards joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 19/02/2020 7:15 pm
Area51
(@area51)
Reputable Member

@dz-1

STL files have no scale information (imperial/metric) and it is up to the loading software (PrusaSlicer) to guess the scale. Most 3D printer programs use metric by default - some use automatic scale (2540%) if the loaded model is very tiny.

When you change the measuring system in the CAD program it is respected internally but the exported STL file is unit less and expect that the receiving program uses the same measuring system. That is why your model is small regardless of CAD system metric/imperial setting.

Take a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 20/02/2020 12:55 am
Kenn
(@kennd)
Estimable Member

I found this topic interesting, so I did a small  test. I use sketchup 2017 make ( standalone ver.). I do all my work in metric. When I export as .STL I am asked what unit of measure I want to use for export. In test it was good thing I did not select yards, meters, miles or kilometer. 😀 I chose inches and when I loaded it into PrusaSlicer, I could barely find it. Look closely and you can see the one I designed in metric and exported in inches.

In my case my cad program scaled it down during export

 

This post was modified 2 months ago 2 times by Kenn
Quality is the Journey, not the Destination...
Posted : 20/02/2020 7:21 am
Tim
(@tim-m30)
Illustrious Member

In a duplicate post I suggested a stray data point in his file: essentially something that slicer sees and scales for.

It is always wise to get more than one opinion......
Posted : 24/02/2020 8:44 am
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