SoliForum - 3D Printing Community — STL size problem in SketchUp

Re: STL size problem in SketchUp

2014-02-05T21:17:19Z

Because that is how many mm's are in an inch

Re: STL size problem in SketchUp

2014-02-05T21:05:52Z

ronsii wrote:

As a general rule the .stl file format does not keep size units straight... usually when working with .stl's if you load something and it seem really small just scale it up by 25.4(metric conversion from inches) and if your loaded file seem too big scale it down by 25.4

Just curious, why do you scale it by 25.4?

Re: STL size problem in SketchUp

2014-02-05T06:58:38Z

Hey grob, going offtopic is my middle name I can take either inches or millimeters also I actually prefer mm's when fabricating stuff but since everything else around here is inches.... well I have to be 'biunitable' lol

last time I checked a mm was = 0.0393700787401574803149606299212598425196850393700787401574803149606299212598425196850393700787401574...
so you're pretty close

but when 'they' decided on what an inch was they just picked 25.4 to make things easier.....

and you are right about the stl file thing but I have switched to using blender units anyways

Re: STL size problem in SketchUp

2014-02-05T04:57:16Z

Thanks for the tip, Ronsii. Precision hasn't been a problem with what I've been printing so far. I have some car parts I want to print soon, so I'll use your trick to make sure they're accurate.

Re: STL size problem in SketchUp

2014-02-05T04:41:01Z

sketchup was originally designed for construction uses and therefore only supported 1/16 inch as the smallest unit

*shudder*

Just going to fire a slightly off-topic volley over from the sensible side of the world with the gentle and respectful invitation that either inches or mm are welcome in my life subsequent to any proponent of one finishing recital of an exact approximation of the other:

1 inch = 25.4 mm
1 mm = 0.039370078740157480314960629921259842519685039370079......

That said, STL files just store straight numbers (they don't even have a concept of units), so you get what you get, and might just have to work it out each time...

Re: STL size problem in SketchUp

2014-02-04T19:15:45Z

Hey knowack, If you find that the accuracy is off on your models try making them at 1000X and then when you are all done with them shrink them back, the reason for doing this is sketchup was originally designed for construction uses and therefore only supported 1/16 inch as the smallest unit... so to get it to work with smaller things they did a lot of workarounds and other kludges to fix the problem instead of a rewrite this will show up as errors in sizing if you are trying to get a model to exact dimensions.

I used a metric template also and for the most part it would work... however every once in a while (1 out of 30...) it would mess up and switch back to imperial units, never did figure out what caused it and haven't used SU much in the last couple months so maybe they fixed it

Re: STL size problem in SketchUp

2014-02-04T14:53:00Z

I make wargame miniatures in Sketchup, and print them out on my SD4. I model in actual size (which makes them teeny-tiny in Sketchup), and they always export dimensionally correct to .stl files.

From what I read on the internet, many modelers work at a much larger scale (for ease of use) with the intent of scaling down during slicing. I downloaded a Warhammer insignia from Thingiverse, the the creator's instructions included that approach. Slic3r has the option to set the desired scale during slicing, which I also use to make 'epic' scale models out of my actual-sized ones.

I use a metric template in Sketchup, with grid snap enabled at .1mm.

Re: STL size problem in SketchUp

2014-02-04T13:27:15Z

DonCarmine wrote:

ronsii wrote:
As a general rule the .stl file format does not keep size units straight... usually when working with .stl's if you load something and it seem really small just scale it up by 25.4(metric conversion from inches) and if your loaded file seem too big scale it down by 25.4
How do I scale the image by 25.4?

Object Placement tab, Scale.

Come on now!

Re: STL size problem in SketchUp

2014-02-04T13:12:07Z

ronsii wrote:

As a general rule the .stl file format does not keep size units straight... usually when working with .stl's if you load something and it seem really small just scale it up by 25.4(metric conversion from inches) and if your loaded file seem too big scale it down by 25.4

How do I scale the image by 25.4?

Re: STL size problem in SketchUp

2014-02-04T07:22:06Z

true... but they don't always work right unfortunately... in theory however it's great

Re: STL size problem in SketchUp

2014-02-04T07:20:15Z

When I export an STL from sketchup it gives me a units option. I always pick millimeters and it always works perfectly. We might be using different exporter plugins, however.

Re: STL size problem in SketchUp

2014-02-04T07:16:33Z

As a general rule the .stl file format does not keep size units straight... usually when working with .stl's if you load something and it seem really small just scale it up by 25.4(metric conversion from inches) and if your loaded file seem too big scale it down by 25.4

STL size problem in SketchUp

2014-02-04T04:22:44Z

So I downloaded an iPhone case from thingiverse.com and opened it up in SketchUp just to mess around with it. After a little while I noticed that the size of the case was huge. Is there anyway to prevent it from growing so large? Is there a protocol I should follow when I import and export STL files into SketchUp?

Thank you guys