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opening STL from openscad strange scaling


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Posted · opening STL from openscad strange scaling

Hi There!

I'm a bit new to 3d printing, but already love it! Printing downloaded stuf is going smooth but I want to design my own ;-)

 

I have made an simple object in openscad wich I export as stl file and then open in Cura (lates 3.4.1).

The problem is that cura scales the object extremely and I can't figure out why.

 

In openscad I use the following code:

 

            cylinder(0.1, 0.1, 0.1);

 

When I make a cube all goes well.

 

Any help is welcome an thanx in advance!

Rob

Screen Shot 2018-08-02 at 16.21.31.png

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    Posted · opening STL from openscad strange scaling

    Hi Rob and welcome to the forums.

     

    The reason Cura scales the cube is because of its tiny proportions. You have set the cube to be a tenth of a milimeter big. Check out these Cura settings (and you might want to create a bigger cube ? )

    Screen Shot 2018-08-02 at 16.38.36.png

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    Posted (edited) · opening STL from openscad strange scaling

    Hi Nicolinux!

     

    Changed it!

    I'm having similar (??) problem with the STL generated from following openscad and then opening in Cura.

     

    difference(){
    cylinder(h=30, r1=60, r2=54);
        cylinder(h=30, r1=7, r2=7);
    }

    I'm trying to print a cap for the filament side gap.

    It is a 3cm high cap for both ends, it has a 7mm hole in it.But it turs out real big...

     

    I hope you can guide me towards the solution!

    Kind regards,

    Rob

    Screen Shot 2018-08-02 at 16.43.39.png

    Edited by robwal
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    Posted · opening STL from openscad strange scaling

    Hi,

     

    this looks about right. You speficied "cylinder(h=30, r1=60, r2=56)". "r" stands for radius, so it has a diameter (r*2) of 120mm. Cura does not perform any automatic scalling now and you can see that the object is 30mm tall.

    Take a look at the OpenSCAD documentation for cylinder:

    https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/The_OpenSCAD_Language#cylinder

     

    One more hint - play with "$fn" which specifies the smoothness of the object (facet number). This way you'll get smoother curved surfaces.

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    Posted · opening STL from openscad strange scaling

    Don't go much smoother than this - maybe 4X smoother.  If you go too smooth there are too many points and the printer does very poorly when there are more than 5 points per mm as it is moving.  It can only look ahead 16 points and if that is less than a few mm it slows down just in case it needs to stop on the 17th point.  Slowing down causes overextrusion and ugliness.

     

    I love openScad by the way.

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    Posted · opening STL from openscad strange scaling

    Thanks for the tip GR5! I might nock (twice) on your door for advice one of these days ?  

     

    Rob

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