Holes/thin Wall Problems, But The Render Looks Fine?

Discussion in 'Design and Modeling' started by SirStefan, Sep 11, 2018.

  1. SirStefan
    SirStefan Member
    According to shapeways there are thin wall problems to the point it basically deletes part of the model and creates massive gaps/holes etc. edit: when I say render, I mean when you upload the product. Not the material render, which also has holes in it
    See picture

    yet the render/mesh of it looks absolutely fine?
    I don't get where the problems are coming from.
    I've already ran it through netfabb, meshmixer, and various online tools to try and get a fix but it ends up the same.
    According to meshmixer, netfabb etc there are no holes.
    Now, shapeways initial checks pass and I can apparently order a print, but there's gonna be huge holes in it! how do I fix?
  2. stonysmith
    stonysmith Well-Known Member Moderator
    Thin walls will not generate holes.
    If you have separate shells that are very tiny, then the uploader will remove them. If you have done a boolean join to merge all of the shells into a single shell, then you should not have any holes.

    Also, if your walls are exactly on the thin wall minimum (0.3mm for FUD) then the 3d tools may mis-interpret the dimensions.. that is why a human checks the models before printing.

    The other thing to check here is to see if any of your faces have an inverted normal. If they do, they'll show up as holes.
  3. SirStefan
    SirStefan Member
    Checking the file in mesh mixer, and checking for multiple shells says there isn't any.
    Checking the file on netfabb also comes up with no errors either. I'm trying to get it printed in Versatile Plastic.
    I'm at wits end really, anything else you suggest?
    Is there a way I could get my models for a manual (human) check without having to order it?
  4. mkroeker
    mkroeker Well-Known Member
    Make sure that the dimensions of the part as seen by shapeways match your expectations. But holes that show up only in the wall thickness tool are most likely a bug in that software, possibly a timeout due to the complexity of the model. Likewise, areas marked with "suspect" thickness may actually be alright if they are small surface details - the tool splits the model into small segments that are tested individually.
  5. SirStefan
    SirStefan Member
    Thanks for the info mkroeker!

    Little update; still don't know how to fix it, or if its just a box. I think my model might be a bit too complex.
    In the Versatile Plastic model render it appears to have weird hole type things in the model. Could this just be another bug? This problem affects the second half of the ship as well, but much, much worse.
    Seeming as my hole model (split into several parts) is costly, I'd rather not take a chance and have it be completely ruined.

    I dialled back my modelling back to the base, and seem to have fixed these hole issues by uploading the main body shape to "make it printable" which did kill off some of the detail a bit (much to my annoyance!) and then literally deleting the main body and replacing it with the MIP fixed version. BUT it did fix these hole issues. Making the base model shell 3mm thick, shapeways now says it suspects some walls to be too thin. 3mm should be enough to giver it enough strength to not break, right?
    Doing this though significantly decreased the cost of the model and it's much more likely to succeed, at the cost of some finer detail but this can always easily be added by me at a later date
  6. crashtestdummy
    crashtestdummy Well-Known Member
    Wall thickness is only for printabality and strength is for you to figure out based on your application. Also if your model is hollow it will be full of wax that can't be removed with will add weight and may impart some distortion issues.