Scaling STEP & STL files?

Discussion in 'Digital Design and Fabrication' started by Ironbeard, Mar 6, 2022.

  1. Ironbeard

    Ironbeard Active Member

    Joined:
    Jul 19, 2012
    Posts:
    153
    Location:
    SoCal up in the San Bernardino mountains
    Ok.....got an Ender 3 2V for B-day and have been playing with it for about a week. I downloaded the "CE3V2 Littorio Superstructure V1.1" files from here, but when opened the STL files they are scaled at 100%? However they seem WAY TOO BIG....HUGE!

    On the turrets from the same files, converted from STEP to STL "CE3V2_90-50 AA Turret" they are scaled at 10000%?!? Yet when I input 100% they practically disappear. Can't even see them in Creality Slicer. At 1000% they are visible, but what should I be printing these out?

    What am I doing wrong? Am I doing something wrong or not reading this correctly?
     
    Last edited: Mar 6, 2022
  2. darkapollo

    darkapollo Well-Known Member

    Joined:
    Mar 26, 2008
    Posts:
    809
    Location:
    Carlisle PA
    You can’t print a STEP file. Those are parametric solids used to distribute an editable file type to those who want to make changes. Converting STEP to STL is not a good idea. A CAD program is going to be able to do that correctly.
    Make sure you are importing the right unit type. If the file was made in MM and your slicer is importing as inches, you’re going to have a HUGE part. STL files are ‘unit less’ so the slicer sees the XYZ coordinates for the triangle and just assumes it is what ever default unit type is you are using.
     
    Last edited: Mar 6, 2022
  3. Ironbeard

    Ironbeard Active Member

    Joined:
    Jul 19, 2012
    Posts:
    153
    Location:
    SoCal up in the San Bernardino mountains
    OOooooooh that makes sense. I have Fusion 360, but I'm at the baby step stage trying to figure out how to use it.
     
  4. darkapollo

    darkapollo Well-Known Member

    Joined:
    Mar 26, 2008
    Posts:
    809
    Location:
    Carlisle PA
    Try changing the default units in your slicer.
     
  5. Ironbeard

    Ironbeard Active Member

    Joined:
    Jul 19, 2012
    Posts:
    153
    Location:
    SoCal up in the San Bernardino mountains
    So what is the best way to get a STEP file into my Ender 3 2V to print out correctly? Yes....I'm that ignorant.
     
  6. darkapollo

    darkapollo Well-Known Member

    Joined:
    Mar 26, 2008
    Posts:
    809
    Location:
    Carlisle PA
    Upload it to Fusion360 and then you can export to mesh. That will make a 3MF which is a ‘unit preserved’ mesh file. Your slicer can open those too.

    I can check the file too in a minute.

    I cannot find that file in the resources… who uploaded it?
     
    Last edited: Mar 6, 2022
  7. Ironbeard

    Ironbeard Active Member

    Joined:
    Jul 19, 2012
    Posts:
    153
    Location:
    SoCal up in the San Bernardino mountains
    Last edited: Mar 6, 2022
  8. darkapollo

    darkapollo Well-Known Member

    Joined:
    Mar 26, 2008
    Posts:
    809
    Location:
    Carlisle PA
    Cool. I did grab the right files. They look right in my slicer. Can you share a screen shot of what they look like in yours? I don’t use the Creality slicer so not sure on the set up for it.

    upload_2022-3-7_6-57-19.png
     
    Last edited: Mar 7, 2022
  9. Ironbeard

    Ironbeard Active Member

    Joined:
    Jul 19, 2012
    Posts:
    153
    Location:
    SoCal up in the San Bernardino mountains
    Can't seem to figure out how to do a screen shot in Creality. However the image as input is basically standing on it's nose outside the print platform at approximately the 5 O'clock position. Not sure why it's showing like that. I'm all new to this so my manipulation skills are sorely lacking at the moment. I can maneuver the image into a position like you have above, but I'm not sure about the scaling. For it to look like your image in relation to the print platform I have to reduce the size 56.49%.

    I'd love to figure out how to print a superstructure like this, (hollow if possible for weight saving) and at some point do all the "little details" that would make it really shine. And it would save a lot of time over building with balsa. Plus If I master PETG it would be pretty battle hardy. I Think I'd have to do quite a bit of support bridging but that's cool as long as the outcome looks correct. I know....dream on.

    Not sure how to do measurements in Creality. With the image I have at the moment:

    Width: X axis = 114.0705 mm @ 56.49%
    Length: Y axis = 485.9873 mm @ 56.49%
    Height: Z axis = 154.79 mm @ 56.49%

    Curious as to what measurements you have for the above dimensions and if I can somehow match those in Creality Slicer program?

    How would I divide up/chop sections for printing. I've started the tutorials in Fusion 360....so far I suck. But I'll keep at it. I'm sure it will suddenly click.
     
    Last edited: Mar 7, 2022
  10. darkapollo

    darkapollo Well-Known Member

    Joined:
    Mar 26, 2008
    Posts:
    809
    Location:
    Carlisle PA
    If you are using Windows just use the "Snipping Tool" to do a screen grab. (just search 'snip' and it will come up). You can then paste that into the text box (ctrl V).
    When I loaded that superstructure it was also standing on its face. I just picked a flat bottom part and told it that triangle should be on the build plate. But Im using Simplify3D, not sure what the options are in the Creality slicer.
    Here are the dimensions from Simplify3D
    upload_2022-3-7_12-38-20.png

    When I scale it down to 56.49% it matches your values.
    upload_2022-3-7_12-37-45.png

    Do you realize that the Littorio is not a small ship at 144 scale? From the front of barbette 1 to the back is going to be that 860mm. The ship overall is 1672mm long. JUST about 3 inches shorter than a Bismarck at 1736mm.

    Here is the 100% scaled Littorio next to my Bismarck superstructure (pieces)
    upload_2022-3-7_12-46-28.png

    Designing and printing a superstructure are a bit advanced. That Littorio has not been optimized for printing so that is a big challenge. Even my first superstructure pales in comparison to the ones I make now. There are a lot of design considerations you need to make so things line up and print with minimal support or issue. Not having everything all stuck together is one thing. Adding alignment pins, or interlocking slots and tabs, etc. are all things to consider when designing these so the average builder who might not be all that savvy can just load it up and hit PRINT. Greg was one of the first to be making superstructures and that file is 6 years old; a lot has changed in terms of making things actually printable since then. I try to make everything fit on an Ender3 since the 220x220 bed size is pretty standard as the smallest 'usable' size.
     
  11. Ironbeard

    Ironbeard Active Member

    Joined:
    Jul 19, 2012
    Posts:
    153
    Location:
    SoCal up in the San Bernardino mountains
    OK, got it. I knew it was big, just not sure of scale when looking at it in this format....3D drawing configuration on a computer screen. My first R/C ship was the HMS Repulse, in the traditional way, but that was over 20 years ago....crap....30 years. Man I'm getting old!! DAMN! Hmmmm? Probably better I start with something CONSIDERABLY smaller to 3D print. Maybe a Capitani Romani? A light cruiser. I've already played with printing out the turrets from a file that I got off here. That should be do able. Hmmmm maybe a destroyer? Never enough of those and they are fun to run. Destroyers with very light superstructures would be nice on the weight saving side. Then ballast could be kept very low and minimize the heeling process.