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bhudson

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  1. I'm not aware that use of OBJ needs a license from Wavefront (presumably Autodesk now). Do you have any evidence of that?
  2. And that answers the question I came back here to ask... 10 microns, thanks! I've been doing 1/256 meter in-game, which is 1/256 cm when I output at 1:100, or about 40 micron. When I scale that down to .1 scale in Cura to get a quick prototype, I was noticing weird things happen in some cases -- that explains some things.
  3. Don Milne: The precise problem definition I might write as: you have a bag of triangles in R^3 and a normal for each. For each triangle, find a connected flat region with the normal in one direction, and a connected flat region with the normal in the opposite direction. Find their geometric intersection, delete it. This is a trivial problem, by which I mean, I could imagine sending a fourth-year student to solve this for an independent project and I'd give them an A for effort when they don't quite finish. Daid's result and the fact that the staircase doesn't cause trouble indicates that it wasn't as bad as solving that full problem: seems that the problem is only if you have a set of triangles on one side that has the same vertices as a set of triangles on the other side (maybe it's just quads?). That's a much easier problem; I'm surprised I couldn't find any free software to solve that. So I spent the afternoon writing it up in my export process. Removes 28 triangles from my test scene, which is exactly the number I expect (6 wall-window and 1 window-window connections, 4 triangles each), and the following loads exactly as I hoped with default options: https://drive.google.com/file/d/0B8Xjxc1Q7X_LOFZON0x1STM1bWM/view?usp=sharing
  4. gr5: I did this in my game, http://imaginary-spaces.com. I generate all the geometry in my code, but it's a bunch of separate objects -- there's windows, stairs, walls, floor, all of them procedurally generated. The normals are correct in all the other software packages I've used (unity, meshmixer, meshlab, blender, ...), so I'm surprised you think they're backwards for Cura -- how do you see that? Also, the picture frame doesn't matter; I took it out and got exactly the same behaviour. Daid, cool! But that seems to point to a bug: in the cube example, if you remove the four triangles in the middle, you'd get a long rectangular prism with normals all pointing out, and life should be good. So there's apparently some bit of logic that gets confused. Following this lead, I loaded up this-file-busts-cura (apologies to Guthrie) in blender and removed one of the overlapping quads between the wall and the first window clockwise from the stairs. That let that window print correctly. Other parts were still wrong (unsurprisingly), and the weird gash showed up elsewhere. Now I'm looking for free software that can post-process an STL file and fix polygons that point opposite each other... anybody hear of some?
  5. I'm not blaming anyone, I'm asking how to fix the issue. Surely there's a way to tell Cura "this is a cube, its interior is this way" and "this is another cube, its interior is the other way".
  6. Here's a very simple STL file; it consists of two cubes that are precisely overlapping. I generated this procedurally (a python script). Cura with default settings (fix horrible type A) slices this to have one cube filled, and the other cube empty with no top or bottom layer. The problem seems to be that in the middle of the model, there are two quads in exactly the same place -- bitwise identical -- pointing in opposite directions. The slicer seems to have trouble determining what's in and what's out. "Keep Open Faces" seems to help a bit, but it's still only generating a shell on the one cube, not both. Adding "Extensive Stitching" and "Keep Open Faces" seems to get the best results here. However, I'm not just printing two cubes -- that was a small test example related to my big program (imaginary-spaces.com) that procedurally generates buildings. And there are scenes that sometimes I can't get to print properly. An example that I can't get to print nicely: https://drive.google.com/a/imaginary-spaces.com/file/d/0B8Xjxc1Q7X_LM0poSUtwQl9NN28/view?usp=sharing With just Type A, half the walls are empty. Adding "keep open faces" leaves a gash. The gash doesn't close up when I add extensive stitching. With just extensive stitching I get the best result, but still no top on the three windows, and still that weird gash (which is not present in the STL file itself). My program is outputting chunks of wall, windows, and stairs procedurally, one by one. They land at bitwise identical locations because that's how the math ends up. I am wondering what I could do that would help Cura discover what's in versus out.
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