Too thin, too many shells- Revit>stl>blender>here

Discussion in 'Software and Applications' started by phoulx, Mar 22, 2010.

  1. phoulx
    phoulx New Member
    Hi all-

    OK, my cute little experiment has now become a thorn in my side. I've got a model of a steel framed building that I would like printed. The original software is an architectural program (Revit) which will export to stl but it's really intended to create building plans not plastic models. I can fatten up my wall thickness to some degree in Revit but now I'm also seeing a "non fixable 800 shells" error. Before Mesh Medic was introduced, I could not even upload the whole model. The building walls and foundations were non-manifold even though they were solids to Revit. With Mesh Medic, I can at least upload the model but it does not pass further tests and is canceled.

    Can the shell problem be easily addressed with Blender? I'm not to keen on learning blender for the sake of this experiment.

  2. iguffick
    iguffick New Member
    Can you put up a file?
    Then we can see how bad (or not) the problem is!

    Blender is hard to get started with, but it very soon becomes productive. You can get the basics by running through a few simple tutorials.

    There are quite a few blender users on this forum. I'm sure most will give you help if you get stuck.

  3. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    Either like Ian said, or have you tried meshlab? It's a free software that can fix some manifold issues in STL's. And it's fairly easy to use.
  4. phoulx
    phoulx New Member
    Here's is a portion of my stl file directly exported from Revit. These walls are the big problem. Inverted Normals, Bad Edges and Shells like crazy.

    Attached Files:

  5. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    Hmmm wow, it has missaligned sheets everywhere, can you put up a dwg? maybe it'll do a better job with that...
  6. phoulx
    phoulx New Member
    Here's a dwg too. This even has a bit of the steel framing for a little better idea of what I'm after. I've sent it to Autodesk also and they're taking a look at it.

    Attached Files:

  7. iguffick
    iguffick New Member

    The STL imported into Blender, and needed a 'Remove Doubles' to join duplicate vertices.

    You have LOTS of extra internal faces, just about every join in a wall would need fixing.

    As an example, the section highlighted in this picture has 6 extra faces.


    Once you select the faces and delete them the model seems mostly manifold. But there are so many of these, you will be there some time!

    I don't know if MeshLab or AccuTrans will be of any help in removing these extra faces?

  8. phoulx
    phoulx New Member
    Thanks for taking a look. That's exactly what I was seeing and thought I was misunderstanding it. I hope Autodesk can give me a clue before I jump in with Blender. I'll keep you posted.
  9. Youknowwho4eva
    Youknowwho4eva Shapeways Employee Community Team
    It appears that Revit doesn't have a Boolean Join operation? I think if you joined all the solids before export, that would help a lot. Everything else pretty much the same as iguffick said. I wouldn't know how in Blender, but the way I was thinking about doing it (would take a while but should work) is to go through and stitch all the surfaces into individual solids and join them like Revit should have.
  10. EricFinley
    EricFinley New Member
    In my experience NetFabb is pretty good at dealing with things like this. Do it following a Remove Doubles operation in Blender, although in my experience all STL files imported into Blender need that anyway (at least with 2.49b's built-in STL importer).