opening STL from openscad strange scaling

[robwal 0]

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

[Nicolinux 288]

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 ? )

[robwal 0]

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

Edited August 2, 2018 by robwal

[Nicolinux 288]

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.

[robwal 0]

Hi Nicolinux!

 

Got it! thanx a lot ?

 

Rob

[gr5 2,172]

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.

[robwal 0]

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

 

Rob