Shapeways upload filter misses overlapping pieces

Discussion in 'Technologies and Hardware' started by Oskar_van_Deventer, May 26, 2009.

  1. Oskar_van_Deventer
    Oskar_van_Deventer Well-Known Member
    Hi Joris et al,

    Today I received my order. There is an error that immediately jumps to view. Some pieces are fused together and 3D printed as a block.

    Here is a photo of the fused pieces.
    Fairly Twisted - overlapping pieces 3D printed.jpg

    I checked the STL file. The mistake was obviously my own. When placing the pieces in the STL file, some of them overlapped.

    Even though it is my mistake, I am a bit disappointed that the Shapeways upload filter did not spot it, especially as it is doing a perfect job in spotting all my other STL errors.

    Maybe the upload filter can be further improved to spot these mistakes as well?

    Thank you.

    Oskar
     
  2. fracai
    fracai New Member
    I consider this a feature, as it allows building more complex models without merging every component. This also allows you to easily build hollow structures without merging the inner and outer shell, as long as the inner shell has inverted normals.

    Perhaps a warning could be posted, but I hope the filter doesn't ever reject models with this feature.
     
  3. joris
    joris New Member
    Oskar + Fracai,

    this is indeed an interesting one. Currently we would not see this as a mistake but rather an intention to make everything one piece.

    I'll talk to the development guys on how/if we could change this or give people some kind of warning.

    Joris
     
  4. Jettuh
    Jettuh Well-Known Member
    well to be honest, no offence to you Oskar, but why would shapeways need a filter for that?

    how could the upload system see if that's correct or incorrect?

    if you mean by: there are more objects overlapping each other,, i would say this:
    Most of the things i upload are models that are build from over 20objects (like the shapewaysbike i created, it has about 50objects that will form the bike)
    So that means i will get al sorts of errors from shapeways cause of overlapping objects

    I think it's just somehting you have to look out for yourself!

    if i'm totally wrong,, then your totally right :D
    and again Oskar, niets persoonlijks hoor (nothing personall)
     
  5. stannum
    stannum Well-Known Member
    As others have pointed, in some cases this is a mistake and in others a helper. The obvious cases, pretty common in sculpture-like models (vs technical shapes), are that it would force precise positioning (no overlaps, no gaps) or really complex meshing that could hit the maximum number of triangles.

    A compromise would be a "your model has X cm3 of overlap volume" report for those cases in which it is non zero. I suppose this would also help optimize models to adjust billing to real material usage, but not locking out people.

    stannum