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Fixing my mesh normals

polycounter lvl 12
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DOG-GY polycounter lvl 12
i have a problem with importing some stuff into 3ds max. so basically our models come in triangulated and with the polygon normals facing in really awkward directions. Is there a good way to select normals based on the directions they face? Ignoring backfaces isn't working all that well in this case. Basically we need to get the normals facing in proper directions so we can weld this all together (the mesh came in split) and then quadrify the mesh.

We need to get some building models from ArcGIS to Unity but the mesh always comes out messed up in the conversion process.

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  • Giometric
    By awkward directions you mean the sections of objects are randomly flipped one way or another right? I'm not sure about 3dsmax, but if you happen to have access to Maya, it has a tool called Normals > Conform that may be able to fix these for you. You'd do a Mesh > Combine on the parts you want to unify, then Normals > Conform. After that the polygons should all be facing one direction, at which point you can just flip them if they are backwards. You might have to do this in sections depending on the shapes to keep the conform working properly but it'll probably be loads faster than flipping every poly manually.
  • DOG-GY
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    DOG-GY polycounter lvl 12
    Thanks for the reply!

    Yeah, they're flipped randomly. We may have access to maya, but at this point I can't be sure, and since we don't have experience with it it probably wouldn't be viable for a long term solution, where we need to do this with a whole campus worth of buildings. I'll look into it though!

    Could someone translate this to Max?

    e: I found an easier way for us using max's unify and flip under the normals modifier over and over again. I found that as a suggestion in a google search and it's working quite well! It sill leaves a few issues, but nothing that isn't fixable. For long term we're still looking for a more straightforward conversion solution
  • RappyBMX
    RappaTools3 has that kind of stuff... if you can send me the model or the models i can do that for you :)
  • DOG-GY
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    DOG-GY polycounter lvl 12
    It's work stuff so I can't send anything out.

    Currently our two options are to remake the models from scratch, which isn't good when you need to make as many buildings as we are, or to fix up the meshes that we can import from ArcGIS. Flip and unify have worked to fix the randomly flipped issue, but now it's got nearly half the mesh facing in wrong directions! It would be a day-2 days work to fix the normals for everything, and that's not going to fly for long!

    Surely someone's done this conversion process before?
  • Ace-Angel
  • Mark Dygert
    It's kind of hard to think of suggestions without seeing whats going on but I'll throw out somethings.

    What happens when you apply a "Edit Normals" modifier and click reset? There might be some other tools in Edit Normals that could help automate stuff.

    Are the faces actually randomly flipped or are they all inside out? If they're randomly flipped, you can use the unify normals script to get everything facing the same direction.
    http://www.scriptspot.com/3ds-max/scripts/unify-flip-normal-polygons
    Oh hahaha Ace beat me to it, that's what I get for getting distracted by scriptspot news

    Are you sure you're not having trouble with smoothing groups and they just need to be reset, you can do that in edit poly? Sometimes those get jacked up easily when importing.

    Have you tried the reset Xform Utility?

    Have you tried creating a new box, applying edit poly to it and attach your mesh to the box? Sometimes that will re-calculate the normals.
  • DOG-GY
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    DOG-GY polycounter lvl 12
    We were able to get it working using spline outlines of the building! Thanks for all the help!

    E:
    Just for the sake of clarification, though it's resolved:
    Yes, it was a normals issue, not smoothing. I tried xform as well as the attaching a box trick.

    Thanks though!
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