3D STL Sizing

[drezal]

Good morning all.  Well, my extremely affordabl e ($199 at Monoprice) 3D printer arrived on Friday and I've been goofing around with it for the last day and a half.  First off, 3D printers are really cool things to tinker with.  It won't replace my CNC by any means but is another fun tool in the shop.

Here's something I've noticed though, when I export an STL file from Gearotic, say of an escapemen t ratchet and pallet and then run the parts through Cura the actual print is about 25%+/- smaller.  If I create a part in, say Tinkercad, and output that to Cura the actual print is extremely close to the design.  I've searched all through the Cura settings, as well as online research and I'm not finding anything.  I saw Art's comments on a prior thread that the STL outputs from Gearotic are absolute and should be correct but this baffles me.

Dan

[Nate]

STL files don't have units, so it's not unusual to have to scale one.   Though, typically, the scaling involves mm to inch conversio ns which is roughly a factor of 25, and not a factor of 25%.

[ArtF]

Hi:

  Yes, I find it hard to say why this would occur. STL's are just a list of triangles
and their corner coordinat es, all of which are absolute , size really shouldnt change
from stl to stl.. other than a normal metric->Imperial conversio n factor at best..

  Let me know if you see anything that seems to show why this is so, Ill take
note of it and give it some thought.. ..

Thx
Art

[Mooselake]

Cura has a one centimete r grid on the virtual build surface.  Do you see a 25% reduction there, or only when printing?  That'll let you know if you need to look at the gearotic stl files, or your new printer's calibrati on, as the source of the issue.

I don't use Cura very often, but I did load an object I printed over the weekend and it passed the eyeball size test.

Other than size how do you like the printer?  Work pretty well out of the box?  Engineer girl's going to be here in just under a month so I've still got some time to think about it, and I'm wondering if I want to surprise her with a Mini.

Kirk