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  1. #11
    Quote Originally Posted by curious aardvark View Post
    you want use mm NOT inches.
    also have a look at Openscad - things like that are doable in minutes and it only outputs fully manifold printable models.

    I also don't see any holes in the case for you to plug stuff into the board. is that deliberate ?

    How big is it ? if convert directly from mm to inches its 11.7 inches by 6.26 by 2.14
    That's pretty big for a pi case.
    So in the STL there is 2 items: 1 is the lid, and the second is the enclosure itself. For whatever reason Meshmixer read both pieces as one build.

  2. #12
    @fred_dot_u
    Im not sure as what all you need so:
    L = 5.5in(139.7mm)
    W = 6.25in(158.75mm)
    H = 1 13/16(46.0375mm)
    Wall, Base, Lid = 1/8in(3.175mm) thick

    Blue = RPi standoffs
    Yellow = Power Distro Standoffs
    Orange = 2-CH relay standoffs
    Black = Lid
    Enclosure Mk2 (2).jpg
    ^^That is what I am trying to make. Unfortunately, SketchUp doesn't have any way of showing overlaps or malformed planes.
    Attached Images Attached Images
    Last edited by 3Dn00b; 04-04-2018 at 02:04 PM.

  3. #13
    Staff Engineer
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    You won't want to import a known defective STL into OpenSCAD. The idea is that I can help by recreating the model in OpenSCAD and provide you with an error free STL, or you can learn to use OpenSCAD to construct the part yourself.

    Let's say the lid is 5.5 x 6.25 x 0.25 dimensions.

    It's better to use metric in OpenSCAD, converting: 139.7 x 158.75 x 6.35, rounding for ease of use: 140 x 159 x 6. If you require fractional millimeter precision, it's an easy matter to plug the more accurate numbers into the code.

    Code:
    module lid(){
         cube([140, 159, 6]);
    }
    lid();
    You don't have to use modules, but it makes things easier in the long run. Also it is a good idea to use parameters defined at the start of the code:

    Code:
    lid_w = 140;
    lid_d = 159;
    lid_t = 6;
    
    module lid(){
         cube([lid_w, lid_d, lid_t]);
    }
    lid();

    I wanted to expand a bit on the parameters part and got carried away. OpenSCAD allows you to pass parameters to modules when you call the module. I colored each panel differently, making it easier to see and identify them. Keep in mind that OpenSCAD doesn't add color to the model and the colors will vanish when the model is rendered (F6), but it does show when the model is previewed (F5).

    Code:
    lid_w = 140;    // also base width
    lid_d = 159;    // also base depth
    lid_t = 6;      // also wall thickness
    wall_h = 25;    // arbitrary guess at wall height
    addabit = 0.1;   // fudge factor for clean unions
    
    module lid(color_choice_lid){
        color(color_choice_lid)
        cube([lid_w, lid_d, lid_t]);
    }
    
    module left_wall(color_choice_left){
        translate([0, 0, lid_t - addabit])      // elevate wall to be not quite above floor
        color(color_choice_left)
        cube([lid_t, lid_d, wall_h]);
    }
    
    module right_wall(color_choice_right){
        translate([lid_w - lid_t, 0, 0])        // use left_wall module, shift it over
        color(color_choice_right)
        left_wall();
    }
    
    module front_wall(color_choice_front){
        translate([0, 0, lid_t - addabit])      // same elevation as before
        color(color_choice_front)
        cube([lid_w, lid_t, wall_h]);
    }
    
    module back_wall(color_choice_back){
        translate([0, lid_d - lid_t, 0])
        color(color_choice_back)
        front_wall();
    }
    
    lid("black");
    left_wall("yellow");
    right_wall("green");
    front_wall("blue");
    back_wall("red");
    test box.jpg

    The great advantage of using parameters is that you can change the value in the assignment area and IF the code is well-written, everything adjusts properly. A good way to test code is to change these figures to ensure that everything else does change appropriately.

    I'm not a code wizard, but find this program to be great fun for the brain cells and very useful overall. There's a strong possibility that just about anyone else familiar with OpenSCAD can improve on my thrown-together code. I didn't put a lot of work into it and may have made some trivial errors, but the model generated is manifold and fits the parameters. Advanced coding escapes me.

  4. #14
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    I'm not sure how I missed the previous message, but it's not a great problem, as one can easily replace the figures in my code with the corrected ones.

    The next question at hand is what diameter are the stand-offs (corner rectangles, center cylinders) and the holes within?

    Use the lower left corner of the box, the outside point as a reference for the center of the holes and measure x and y from there. Also include height for obvious reasons.

    I'll modify the code I just placed to match the information provided and re-post, as it's not going to be particularly large.

  5. #15
    Enclosure Measurements.jpg
    Here are the measurements and conversions...as best i can make em lol
    (They are really strict about file sizes lol)

  6. #16
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    The drawing is kinda shaky as an engineering drawing, but I'm making the best of it. A well-drawn model will have all dimensions referenced from a single point, typically for this one, it would be the lower left corner. That's not a big deal, as I can do the math and get correct results. Questions to be answered are preceded by stars **.

    There are some missing dimensions and some ambiguous ones as well. The answers may be in the drawing, but they are pretty well hidden/obfuscated/located in an unusual manner.

    You have a 1/4 square block in the lower left corner. The diagonal dotted line with 3/8 at the end of it is ambiguous. The diagonal of a 1/4" square is 0.3536 inches, not 0.375 inches. There's no need to have a diagonal dimension if the other two are provided. ** Please confirm that the 3/8 dimension is meaningless?

    Please also confirm the same for the right side corners, top and bottom. The diagonal of a half inch square is 0.70 inches, not 0.75 as shown in the drawing. ** Another meaningless dimension?

    ** Does the 3/16 center notation in the lower left corner mean that the hole is to be 3/16 inches diameter? I hope it's not that large, because that leaves a too-thin wall on the standoff, a thirty-second of an inch at the very edges.

    The four standoffs in the lower right corner are almost clear. The dimensions of the standoff are in a good location and the y-spacing and x-spacing for the set as well as the y-delta are in the drawing, but it seems to be missing the x-delta, the distance from the edge of the drawing (left edge or left inside, either one). As the rest of the drawing references the inside of the walls, let's be consistent and provide that figure based on that reference.

    ** The upper left standoffs have most of the necessary information, but in this case, it's missing the x-delta and the y-delta figures. Again, it should be referenced from the bottom and from the left, but if you provide it from the top and from the left, I'll do the math.

    ** Can you clarify the note to the far right of the drawing, "standoff inner = 1/4, center 3/8 from inner corner" ? To which standoff(s) does this apply? One typically does not measure on a diagonal, so I would not apply it to the dotted diagonal lines in the corners. If this is a reference to holes in the right side standoffs, it's peculiar, as one would simply center the holes in the square cross-section.

    I've been running over the drawing for too long tonight and will have to get back to it tomorrow. I'm sure there will be more questions, but you've given me a good bit with which to work.

  7. #17
    Quote Originally Posted by fred_dot_u View Post
    ** Please confirm that the 3/8 dimension is meaningless?
    This dimension is the distance from the bottom left inner corner, to the top right of the bottom left standoff. Sort of a double check during my SketchUp work to verify that the measurement for both sides is the same.

    ** Another meaningless dimension?
    Again just a double check for accurate measurements.

    ** Does the 3/16 center notation in the lower left corner mean that the hole is to be 3/16 inches diameter? I hope it's not that large, because that leaves a too-thin wall on the standoff, a thirty-second of an inch at the very edges.
    3/16 is the distance from the bottom left inner corner to the center of the standoff. Another double-check during SketchUp work.

    ** The upper left standoffs have most of the necessary information, but in this case, it's missing the x-delta and the y-delta figures. Again, it should be referenced from the bottom and from the left, but if you provide it from the top and from the left, I'll do the math.
    In Fig. B: the dotted lines just intersect for the final standoff location. Same as Fig. O.

    ** Can you clarify the note to the far right of the drawing, "standoff inner = 1/4, center 3/8 from inner corner" ? To which standoff(s) does this apply? One typically does not measure on a diagonal, so I would not apply it to the dotted diagonal lines in the corners. If this is a reference to holes in the right side standoffs, it's peculiar, as one would simply center the holes in the square cross-section.
    Another double check: from top/bottom respective inner corners to center of the standoffs. SketchUp camera views arent great even when i can control em lol.

    It may be double work, but any time i do measurements i measure more than 2 or 3 angles to verify points are correctly plotted.

  8. #18
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    Wow. I'm not sure how you got SketchUp to tell you that the diagonal distance of a 1/4" square is 3/8". That's not a double-check, that's a contradiction. Either the diagonal distance is 3/8" and the edge of that corner square is 0.2652 which is 0.0152 larger than 1/4" or the diagonal distance is 0.3536", not 0.375" and the corner square has a side of 1/4". Here's the key though. The variation of those numbers is so small that it won't really matter to the construction. I'll stick with the orthogonal figures, as diagonals are not used for measurement in the typical engineering drawing and as you can see, really throw off the references.

    lower left corner.jpg

    I'm hopeful the drawing above will enlarge well enough to view. The hole in the standoff is 1/8" and is centered in the square. The two large standoffs have no ambiguities. They are defined for inside and outside diameters and placement from the bottom and placement from the left. ** Please confirm hole diameter for corner standoff. **

    lower right corner.jpg

    This one is a bit more undefined. There is a measurement for placement from the bottom, but ** no measurement for placement from the left or right **. Hole diameters are clearly understood. The hole diameter in the square corner standoff is 1/8" and centered.

    upper left corner.jpg

    This array is lost in space. All that is needed to anchor it is ** the measurement for distance from left side and the distance from the top (or from left side and distance from bottom). **


    The drawings currently do not show height of the standoffs, as that information is clear in the sketch and I kept the Solvespace images to 2D for clarity. It's easy to clutter up a Solvespace drawing with dimensions and constraints. 3D imaging in that program gets even more fun.

    If you right click on the images and save them to your computer, they will be larger and easier to view.

  9. #19
    Top left standoffs(Fig B):
    From top: 7/16(11.30)
    from left: 1/2(12.78)

    Bottom right standoffs(Fig O):
    From right: 1in(25.62)

    Corner standoffs match wall height which is 47mm

    Bottom left corner standoff diameter is 1/8(3.59)

    Conversions are via a digital caliper.

  10. #20
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    I think those numbers fill in all the blanks. One important observation, though, is that most manufactured electronics today are on boards that are measured in metric. You've provided Imperial units, converted as you said to metric. There's going to be some errors in the conversion, especially when you 3D print this. You may want to check the manufacturer's specifications for hole placement, to see that they are likely measured in millimeters to the whole number and not to decimal equivalents from Imperial units.

    Because I'm using Solvespace for the drawing, it toggles easily between metric and imperial, but the OpenSCAD model will be in decimal millimeters, to two decimal places. It's not necessary to stretch it out to three or more, simply because a 3D printer isn't going to give you that level of precision anyway. That sort of logic will probably get you through any rounding errors from imperial to metric or the reverse.

    I hope to be able to put some time into the standoff placement in OpenSCAD today and will post if other questions arise.

    If your calipers are converting one inch to 25.62 mm, it needs to be replaced or repaired. One inch is 25.4 mm.
    Last edited by fred_dot_u; 04-07-2018 at 03:09 PM.

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