The line between detail and wall

Discussion in 'General Discussion' started by Razoric480, Jul 9, 2013.

  1. Razoric480
    Razoric480 New Member
    A model I put up was given print runs in a couple material (WSF and FD) successfully. However, upon attempting to print it in WSF polished, the model was rejected for parts I thought were more like surface detail, hence why I didn't double measure them or make them thicker.

    In the image below, I can see that the top of the leg may be more of a wall, so that'd be my own fault. But surrounding the exhaust hole, I feel that is more of an emboss-and-engrave rather than a wall.

    So my question is, what is the distinction between detail and structure? I'd like to have as complete a checklist as I can before I order prints. It's not so bad at the moment since we're in the prototyping phase, but given the time it takes between being made aware of these issues and subsequently getting a printed prototype, getting it the first time would be nice.
     

    Attached Files:

  2. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    We are currently working on cleaning up our definitions as far as wall, wire, or detail. Between wall and detail is a little easier. A detail, below the specifications for wall thickness, must not be taller than it is thick. So if your detail is .25 wide, it can't be more than .25 tall. For tapered details, the angle must be at least 45 degrees so it never crosses the taller than wide barrier.
     
  3. Razoric480
    Razoric480 New Member
    Mmh, alright. Thank you, that already clears up a lot of confusion.
     
  4. stonysmith
    stonysmith Well-Known Member Moderator
    The usage of the word "wire" was in my opinion, an attempt to clarify a specific topic that has confounded many designers.

    The way I would define it:

    A wire is any shape that has two dimensions roughly equal to each other, where the 3rd dimension is bigger than either of them by a factor of 2.
    It really doesn't matter whether the cross-section of the shape is square, circular, or even 63 sided.

    A wall is any shape where two of the dimensions are significantly larger than the minimum wall thickness and the third dimension is close to the minimum wall thickness OR a wall is any shape that protrudes farther from a perpendicular surface than it is wide.

    A detail is any shape that is attached to a wall and protrudes less from the wall than the it is wide.

    =====
    The real trouble enters the topic is when the cross section shrinks to approximately the wall thickness. These materials are not infinitely strong.. If you make a wire 1cm thick and 10cm long (expensive), that solid block of plastic is not going to break during normal handling and shipping. If on the other hand, you make a wire that is only 0.3mm thick, and still 10cm long, it is possible that it will break under it's own weight if you grasp just one end and hold it out horizontally.

    You also must take into account what is on the ends of the "wire". For any given length of wire, there is a limit as to how much mass can be supported on the ends of that wire before it breaks.