Scale Issue Metric Question

[ednspace]

Quick Question,

Just installed the Personal Edition and have been checking it out. What I would like to do is export my models as STL files and then open them with FreeMill or CamBam to create gcode files for a CNC machine.

I have inches selected as my default setup but yet when I export as STL and open with any other software what was 1 inch shows up as 25.4 inches. (1 inch = 25.4 mm)

For instance if I draw a 1 X 1 X 1 inch cube it shows up as 25.4 X 25.4 X 25.4 inch cube in my other software. Obviously a conversion problem, however is this a standard for STL files or am I missing something simple in the setup.

I could keep the metric in my other software however the control software for the machine I am using is setup for inches and I am a little afraid of creating metric Gcode for it.

Hope this makes sense, thanks for any help,
ED

[Mike Swartz]

CoCreate Modeling Personal edition uses Millimeters as it's base unit, so any data exported from Modeling will be exported as Millimeters.

Conversion to other units will need to be done by the software that loads the STL file. You should be able to set your user units as mm, then load the STL file. After the file is imported, reset your units back to inch.

[clausb]

If I remember correctly (and a quick Google search seems to confirm this), STL files do not carry any unit information with them, i.e. the data in STL files are unitless!

Hence, the receiving software cannot tell whether the sender generated coordinates in mm, inches, or nautical miles, so all it can do is guess. Unless, of course, you give the receiving software some hints, such as by setting options during import, changing the receiver's unit settings et cetera. Since I know neither Freemill nor CamBam, I'm not sure about which settings you'd have to tweak, though.

Claus

[ednspace]

Thank you both very much for the information.

Seems like I need to be looking at the receiving end rather then the sending end of my tool chain. It is good to know positively that CoCreatePE is working in mm units and also that this information is not embedded in the STL file, this should help with my conversions.

This seems like its going to be pretty fun software to play around with.

thanks again for the quick responses,
Eric