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Sketchup fractured planes

Discussion in 'CAD' started by Metalguru, Feb 7, 2016.

  1. Metalguru

    Metalguru Master
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    Hi Guys:

    Another puzzling behavior by Sketchup.

    So, I have a drawing of a plate with holes. I decided I need to change the size of a couple of holes. I drew new hole outlines and deleted the old hole outlines. Sketchup then proceeded to fracture the face of the plate into a hundred little triangular shaped areas instead of one are the size of the plate. Don't understand why this happens. It has happened to me several times in the past as well. Only way to get out of it is to revert to an earlier save before the edits. ***?

    What is the proper way to edit the size (diameter) of a hole without frakking up the surfaces on which the hole is placed?
     
  2. David the swarfer

    David the swarfer OpenBuilds Team
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    I see that only when the 'plate' is not flat, ie one of the corners is not in line with the other three.
    (for a flat drawing) select the plate and all edges, right click, and select Phlat Edge|Phlatten selected edges.
    this will ensure that every point is at Z=0. in fact maybe you should delete all faces first so it can create new phlat ones during this process.
     
  3. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    The plate does start perfectly flat. Something in the hole that is being cut out causes the error and I have yet to figure out what is causing it. I have a feeling this is a rounding error inside Sketchup. This may be the reason many people recommend doing models at 100x scale and then shrinking them when you are finished.
     
  4. David the swarfer

    David the swarfer OpenBuilds Team
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    what size are the holes?

    Sketchup does internal comparisons down to 0.001". (took me ages to figure this out, and it is not documented much either)
    ie , if 2 points are less than 0.001" different, Sketchup thinks they are equal.
     
  5. Metalguru

    Metalguru Master
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    I found a workaround this time, I deleted the original holes (which had relief holes for screw heads around them) completely. This means I had to delete both hole diameters, and the inside faces of the holes so nothing was left. Before deleting the last circles on the face, I used the "find Center" tool to place a center mark on the hole. I then created a new circle on both faces with the new hole size, and deleted the face fragments inside the circles to create the hole. This seems to have worked fine.

    The original hole was 5mm with a 9mmx1.6mm relief cut on one side, the new hole was 4.2 mm for a threaded hole with no relief cut. So, they were way more than .001 different.

    I will try the Phlatten command as suggested by David to see if there is any issues with the surface.

    A side question, how do you put threads in a hole on Sketchup. I notice that the lead screws in the c-beam actuator drawings just seem to be a photo overlaid on the surface of the rod, they are not actual threads. But some of the holes show internal threads, and I can't see how to do this.
     
  6. Metalguru

    Metalguru Master
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    I tried using the RepairBL + Phlatten command, it says it found something but does not fix it. If I click Yes to the repair, it does something and goes away, but if I run it again it still comes up with the same error.
     
  7. Metalguru

    Metalguru Master
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    How the hell do you get rid of this crap? I keep going into Window/Preferences/Extensions and unchecking all the phlatbone stuff, but it won't go away. Even after restarting...
     
  8. David the swarfer

    David the swarfer OpenBuilds Team
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    from what you say here, I gather you are doing a full 3D drawing. This then has nothing to do with SketchUcam at all, since SketchUcam generates gcode from FLAT drawings.

    please watch the videos and read the help first, you need to know more about the tools you are using.
    yes, SketchUcam can cut counterbored holes from a flat drawing (-:
    you draw them yourself, or you search the web for a plugin that does it for you. try
    SketchUcation

    This is the beauty of Sketchup, the plugin system means that you can add whatever you need to the basic system, and most of the plugins are free.
     
  9. Metalguru

    Metalguru Master
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    Thanks David.

    You are right, this had nothing to do with SketchUCam, it was a simple 3d drawing of a plate.
     

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