Objects designed with Fusion 360 are tiny when opened in Slicer software.

[Anonymous]

I am very new to 3D design and 3D printing.  Just purchased my first 3D printer, a Prusa Original i3 Mk3.  I designed two very simple objects in Fusion 360.  I set the units to inches in the preferences for both Design and Manufacture.  The basic shape of the first object I designed was a 3"X6" rectangle about 9/16" thick.  The second object was a triangle with the equilateral sides 3 1/5" long and 1/2" thick.  After saving the STL files and opening them in my slicer software the objects were so tiny I could barely tell what they were.  I have tried it with Prusa Control and Slic3r Prusa Edition and both have the same results.  I don't see any settings in the slicer software that would correct this.  What am I doing wrong?

[jhackney1972]

I do not know specifically about Slicer but in Dremel Digilab, all models come into the application in millimeters.  So if you are designing in inches, it is going to be very small.  Just scale it up, universally, or enter the dimensions of the part translated into mm.

[Anonymous]

Thanks for the quick response. I guess I need to follow up with Prussia support to find out if that is what is going on.

[etfrench · Accepted solution]

Stls in Fusion 360 must be created with the units set to mm.  Settings in Prusa (if they have a units setting) should also be set to mm.

[Anonymous]

Thanks for the responses. I reset my preferences to mm in Fusion and redesigned the parts and they were the correct size when I opened the STL’s in my slicer software.

[HughesTooling · Accepted solution]

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@Anonymous wrote:
Thanks for the responses. I reset my preferences to mm in Fusion and redesigned the parts and they were the correct size when I opened the STL’s in my slicer software.

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You can still design in inches, just change the document to mm temporarily, export as a STL then change back.

Mark

[Anonymous · Accepted solution]

You can typically just change the scale in the slicing software. You just scale everything up by 2,540%. That's always been the easiest for me since I also use my cnc on some jobs. 

[etfrench]

My CNC machine is set to inches, but I usually design in mm.  In Preferences, set the Manufacture units to inches, then Fusion 360 automatically converts the units between the Model workspace and the Manufacture workspace.  Unfortunately, it won't do that for STL creation.

[HughesTooling]

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@etfrench wrote:

My CNC machine is set to inches, but I usually design in mm.  In Preferences, set the Manufacture units to inches, then Fusion 360 automatically converts the units between the Model workspace and the Manufacture workspace.  Unfortunately, it won't do that for STL creation.

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If you can use the custom option from send to 3d print utility Fusion will automatically scale the model to mm. I couldn't get the custom option to work with Slic3r though, works fine with Simplify3d.

Mark

[etfrench]

That's nice.  I hadn't noticed that since I design in mm.  This thread shows how to create a batch file or executable to use Slic3r in the custom option.

[Anonymous]

Mark, are you saying that I can design in inches and then just change my preferences to mm before saving an STL file?

[Anonymous]

Both objects I designed had some dimensions that needed to be fairly precise. I wouldn’t have any idea how much to scale it up to get the right dimensions.

[Anonymous]

Scaling from mm to inches just requires you to multiply by 24.5.

That's why your scale factor in Cura is just 2,540% to quickly convert from the default mm import to the equivalent inches. I would imagine slic3r has a scaling option too.

[Anonymous]

Thanks for the info.

[etfrench]

There is no need to scale outside of Fusion 360.  You can either just switch the display units to mm or you can output directly to Cura, Simplify3d, or Slicer.  Fusion 360 will accurately create the stl in mm.