Cura 4.0.0 Importing AutoCAD 2017 Drawings Very Small

[mesooohoppy 0]

Hello,

 

After an almost 5 year hiatus, i got back into drawing with autocad with the intentions to print small things on the ender 3 pro i have available to me. I chose to draw this belt clip that will help me hold onto ear protection. I set the units in AutoCAD 2017 via the 'UNITS' command to inches as that is what all of my parameters were measured in. 

 

Once i was done drawing the clip, i 'exported' STL file into the appropriate folder on my PC. Every time i import the STL into cura 4.0.0, it is insanely small. im talking half of a pea sized small. as previously stated, printer is an ender 3 pro. i believe our 'profile' for cura is currently set on the ender 3 pro profile that came with cura. 

 

i have to manually scale this clip by taking a measurement of the length in autoCAD, convert from inches to mm and then change the x or y in cura. this works okay, but it is not precise. the thickness of the clip is about .040" (1.016mm) off, so that means every other measurement is off as well. 

 

i even changed the units in CAD to mm, and no changes. 

 

how can i setup autoCAD/cura to ensure that my drawings are automatically scaling correctly? this belt clip isnt a 'precise' part per say, so its not an issue right now. but i plan to start prototyping things that have to print the correct dimensions. i would ask on an autocad forum, but i dont think a lot of people are using autoCAD specifically for 3d printing.

 

thanks in advance, 

Brandon  

[mesooohoppy 0]

I cant edit my first post, but here are a couple of pictures. 

[nallath 1,120]

STL doesn't have units. Cura assumes 1 unit in STL is 1 mm.

[mesooohoppy 0]

thank you. although i still think something is wrong. i dont have my measurements in front of me right now, but i believe the clip is almost 2 inches long. for the sake of ease, lets just say its exactly 2" long.

 

that would suggest it be imported into cura as a 2mm long part. its not 2mm long. its insanely tiny. i have to zoom in as much as cura will let me to select it.

 

as previously mentioned. i confirmed the length in autocad (again, lets just say 2"). converted to MM (50.8mm), and made the changes in cura. after the part was printed and checked with a micrometer, the thickness was off. 

 

looking at the first post, the thickness was off by .040" (1.016mm). which means everything else is off as well. 

 

do you know of any guide that can help me ensure that my scaling is 100% correct? i dont mind manually changing the scale in cura. i just want to make sure i am doing it right. i have some other parts i plan to draw in autocad and they need to be held to a higher tolerance. a .040"/1.016mm + variance will not be acceptable for the outcome for said parts. im really trying to avoid printing something numerous times, just to get the scaling correct.

 

thanks again.

 

[Sandman1221 0]

Select object in Cura 4.1, 6 tabs will open on the left, second one down is Scale, enter 2540% in one box/dimension and also check Uniform Scaling box and it will scale all dimensions to inches.

Edited May 28, 2019 by Sandman1221

[mesooohoppy 0]

thank you for that sandman. i did another part that had to be more precise as it was acting like a gasket. 

 

here is what i did. found the width of the 'gasket' in autocad. i believe it was something like 1.75". i multiplied that times 25.4 and put the width in MMs in cura. 

 

here is where it gets weird. the scaling is never 2540%. ever. its always very close. i believe the scaling for this part was something like 2489.95%. ive drawn two other parts and the scaling percentage is still close (but never 2540%). i have no idea why this does this, but i am now able to replicate successful scaling in cura using my method.

 

im just not sure why im the only one having a problem scaling into cura correctly. ive double/ triple checked my math (not like its hard to multiply something by 25.4), so it would suggest something is wrong with my autocad, cura, or printer. 

 

oh well. my issue has been fixed. looks like i will manually have to scale everything myself.

Edited May 28, 2019 by mesooohoppy

[Sandman1221 0]

I would scale in Cura Ver. 4.1 (newest version) not by multiplying inches to convert to mm, but by entering 2540% into the scaling windows for the X/Y/Z directions.

[gr5 2,172]

The units are not specified in STL files.  It's not part of the STL specification unfortunately.  Cura expects everything in mm.  When you save from autocad to STL there are lots of options and one of them is to choose the units.  Choose mm.  It should remember your units for next time (I assume - I don't use autocad).  There are posts about this somewhere on this forum by people who know autocad better than me - I read those posts but many months ago.