Ring smaller than expected

Discussion in 'Technologies and Hardware' started by epacheco, Oct 7, 2012.

  1. epacheco
    epacheco New Member
    Hi everyone,
    I recently received my first 3d print, which is a simple ring I modeled in Maya (http://www.shapeways.com/model/713197/basket-ring.html).
    I got it printed on White, Strong and Flexible and the dimensions are about 4mm smaller in the printed model than the 3d model.
    Is this a common factor to consider with 3d prints?
    I need to know how to compensate this, since rings have to be sized precisely to a millimeter.
    I loved the quality of the print by the way :)
    Thanks,
    Esteban
     

    Attached Files:

  2. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    You should email service with the link to your model, order number, and pictures showing the size of you print. 4mm is too much shrinkage for WSF.
     
  3. epacheco
    epacheco New Member
    Ok, sounds good.
    Thanks!
     
  4. Fredd
    Fredd New Member
    Out of curiosity, were you using the US size 10 (19.76 mm diameter) and were all the dimensions off 4mm. Post your STL here and will see if anything is off with the model. :)
    Keith
     
  5. epacheco
    epacheco New Member
    Hi Keith,
    Yes, I was using US size 10 (give or take a fraction of a mm) and it's off 4mm in every dimension.
    I'll be posting some pics of the 3d ring and the printed model later when i get home if that helps. I won't post the stl though, for obvious reasons.
    Thanks,
    Esteban
     
  6. Fredd
    Fredd New Member
    No, I was not trying to steal the design, lol Esteban. Was trying to figure out the scale factor where you could scale the model properly, from the STL. Inner diameter mainly. Its not that difficult if you have a dimension from the original model and the finished product
    Original height would do it., for scale factor
    Scale factor= A dimension you want printed/ same dimension of modelling program.
     
  7. epacheco
    epacheco New Member
    Hehe, got it.
    So basically what you are saying, if I understood correctly, is that I should scale up my 3d model to compensate for the scale factor in the final printed model?
    The thing is, I can't see the STL file directly since maya does not support STL. I actually exported a DAE file using a third party plugin, and same with an STL, I can't import it and see it in maya. So maybe in the conversion process from a maya file to a DAE file it got scaled down.
    Once I get a PC I'll get netfabb to check on my future models :)
    Thanks!
    Esteban
     
  8. Fredd
    Fredd New Member
    So the bounding box height from SW is 2.204cm. Take the bounding box height from your maya model, divide it by 2.204,, then scale your maya model by that amount. Uploading a model is free, if the dimensions match from SW and Maya,once uploaded you are. ready to print. I mentioned Meshlab because it can convert many formats into stl, which would help you.
    Besides since scale factor effects height,width, length dimensions when you scale it, according to yucky mathematics should be re-sized properly. Upload, then edit your model to determine if the dimensions work, before you offer it to the evil printers
     
  9. epacheco
    epacheco New Member
    Hi Keith,
    I'll definitely try that out and see if there's a difference in the dimensions that shapeways has vs. maya's.
    I'll be posting back here when I find out :)
    Thanks,
    Esteban
     
  10. epacheco
    epacheco New Member
    So as i mentioned before, I'd be posting here if I found a solution :)
    After speaking with Mihon from Shapeways, we figured out that the model they had was smaller than my maya file. So, it seems that it was scaled slightly down when I exported the file from maya using a plugin I found online.
    He recommended netfabb as a tool to check the final scale of a model before it's uploaded to Shapeways.
    Esteban
     
  11. SGDesigns
    SGDesigns New Member
    Definitely, an STL check should always be done on every model before it gets uploaded onto shapeways.