Odd scaling issue Autodesk

[mthompson239]

If I make a 1" circle .ipt in 2014 Inventor and print to STL, comes into S3D properly.
If I make a 1" circle .ip in 2018 Inventor and print to STL, comes into S3D at about 2.25".

Bring both same .stl files into Slic3r and they are both proper.

Any ideas?

[mthompson239]

Pic for reference.

[mthompson239]

So if I export as a step file from 2018, open in 2014, and then print my .stl...scales proper...VERY odd!

[dkightley]

Its simple to explain....

Firstly, stl files do not contain any information about the scale of the units. Each file has dimensions specified in UNITS....and the units are unspecified.

Your 2014 package is exporting the file where one unit represents 1 mm.....and your 2018 package is exporting the same file where one unit represents 1 inch.

All you need to do is to change the settings in the latter software so it matches the former package....and S3D.

[zemlin]

but 2.25 isn't the conversion for mm vs inches, or cm vs. inches.

[dkightley]

Well...I'm no Autodesk expert. But the essence of what I've explained still stands!!! There's a scaling difference in the exporting from the two installations of Autodesk!

[horst.w]

Import an object and do a double-click on it, a setting window opens.

Have a look to Scale %.
If there is a different value to 100%, DKightley is right.
If the value is 100% but the object comes in different dimension, then the reason is to search by the CAD-program.
S3D or other slicers only fulfill what the STL-file is delivering. S3D is using an algorithme that changes automaticaly the dimension in the range of some Millimeters to inches because it is not very probable that an object to be print is so minor.


Regards
horst.w
GER

[gearsawe]

Have had this problem with a student once. Turned out he had built the part in mm so say 25mm. exported it in "cm" so the program exports and convert to 2.5. The printer software I used at the time assumed inches. the part ended up 2.5inches . So the 25mm (roughly 1inch) ended up being 2.5 inches in the end. the the part scaled up 2.5x roughly. He swears he clicked mm but accidentally click cm as the export units.

if you are having scaling down issue by about x2.5 you might have built in "cm". so you make something 1 which is really 1cm. you export as mm 10mm S3D expects mm the the part comes in as 10mm. this would be 2.5 small than what you thought was a 1inch.

[mthompson239]

All signs point to an exported 1" in model...however, in Simply3D 4.0.1, does not bring in correctly scaled...see attached. Can I not change the default measurement in S3D to IN vs MM to resolve this? As I do not want to have to scale an item within S3D...rather keep it the same as to how it is designed 1/1 ratio.

Much thanks

[mthompson239]

more pics