Discussion in 'Software and Applications' started by daviesbobuk, Feb 27, 2009.

  1. daviesbobuk
    daviesbobuk Well-Known Member
    I am one of those group of people, who use Rhino 3D for their CAD work. Like several people on here, I have suffered greatly from the "manifold" rejections.

    However, I seem to be seeing some light on this at long last, and while not comprehensive, or fully conclusive, here are the steps I have been taking which seem to produce results.

    Create object in Rhino until happy with design.
    Convert to mesh and show edges.
    Use the Rhino tools to fill holes, join naked edges.
    Save as an STL.

    Thanks to other threads on this forum, I have downloaded MiniMagics and MeshLab.

    I look at the STL file with MiniMagics and it shows lots of errors. It is a viewer only so only good as a diagnostic tool.

    I then load the STL into MeshLab and Close Holes, Remove Unreferenced Vertex, Remove Zero Area Face, Remove Non Manifold Faces.
    I save the file.

    Back into Rhino with a new, blank, model and import the STL. Check edges and there are new ones which never existed before. Fill holes, join naked edges again and resave as an STL. I do not bother saving as a Rhino file at this stage.

    Back into MeshLab and Remove Non Manifold Faces, some have usually turned up although we got rid of hem the first time.
    Save the STL.

    Check with MiniMagics and it should be ok and ready to upload the Shapeways.

    These are not definitive instructions, but I have followed this method several times now and it has worked. I hope it will help someone.

    Feel free to correct me if I have managed to get some of this in the wrong order, or have missed something.
  2. jpbrandt
    jpbrandt New Member
    I'm using Rhino4 as well. I'm not getting "manifold" problems...I'm getting perpetual: "Inverted Normals" refusals on all my files. I've followed all the suggestions by Joris and the forums...nothing works. Other companies have no problems with these files. Have you had this experience? Do you have any advice?

    Attached Files:

  3. ArMOO
    ArMOO New Member
    Hi jpbrandt,

    I checked your file and you have to model it again .
    You have some surfaces in the bottom of your product.
    It looks like you filled a hole with a surface and the old hole is more or less still there.
    Also where the 2 tubes colide are some problems.

    I would suggest to make 2 revolves, a boolean to combine them and a fillet where they meet.

    Greetings AO
  4. jpbrandt
    jpbrandt New Member
    Thanks for your time.
    I'm new & self-taught to Rhino 4 and am not yet familiar with all the commands. Could I ask you for a little more detail in the procedure? I know Boolean Union but not how Revolves or fillets work. Is there a certain way I should put together my models to simplify getting them out correctly? Is there a certain protocol to designing a model that I should be aware of?
    thanks again,
  5. ArMOO
    ArMOO New Member
    Hi Jp,

    I only use rhino with vray as a plugin for rendering.
    Best to do the tutorials that come with the software.
    If you sent a technical drawing or a detailed sketch ( take a picture with your cellphone of it ) I can make it for you in solidworks if you want.
    Check also these tutorials.

    Greetings AO

    Attached Files:

  6. ArMOO
    ArMOO New Member

    And another one.

    Greetings AO

    Attached Files:

  7. jorrie
    jorrie New Member
    Using rhino 5 WIP for a personal project,
    OSX edition. Saving as .obj file no problems exporting to shapeways.
  8. Sol3
    Sol3 Member
    Now I'm wondering whether to get Rhino or Power Nurbs for Max.

    Kinda sounds here like it's just too fussy using Rhino. :neutral:

    I was leaning toward Rhino, but again, not so sure now. :(
  9. jorrie
    jorrie New Member
    I think rhino works out fine, if you export to object .obj those load fine in shapeways it seems, not sure about version 4 for windows, i use only version 5 wip for osx wich is free to download for non commercial usage, it keeps improving

    just dont like winblows anymore but i have version 4 of rhino for windows on vmware fusion because the osx version cannot decent print yet, its still a wip work in progress version

    not sure about all the rhino problems around i have fairly complex 3d models i make with rhino without any real problem so far.. stl is just pain obj is fine
  10. Dotsan
    Dotsan Well-Known Member
    Hi, I've been using Rhino for some time, and always use it to create and repair files. There is a steep learning curve but it's paying off now.

  11. Dotsan
    Dotsan Well-Known Member
    Last edited: May 27, 2011
  12. aphollis
    aphollis New Member
    I found it useful to make sure you start your model with the tolerance at .0001" (or metric similar). Do your best to build everything with solids and use boolean commands for as much of the process as you can.

    After every modification do a volume check to make sure your model is still watertight. Most of the time when I encounter a problem it's the result of a fillet or chamfer on a complex solid.

    As far as I know, the only fix for this is to manually join the edges, but I haven't had much luck.

    the .0001 tolerance is the most crucial adjustment i've found for making rhino work with the shapeways system.
  13. billy57
    billy57 New Member
    In my experience, trying to fix a faulty mesh using Rhino's mesh tools will often generate more faults than it heals.

    After much experimentation, I have arrived at the following method. It is rather tedious, but it is simple and it works. It will produce an STL mesh from your Rhino model with no naked edges or other horrors.

    1. Join two parts of the model together, using Boolean. (If for any reason the parts will not Boolean, this indicates a problem which you will need to fix before you proceed.)

    2. Immediately create a test mesh from the resulting combination (Mesh/From NURBS object).

    3. Run CheckMesh. Disregard the first line ("This is a good mesh" or "This is a bad mesh"), as a 'good' mesh from Rhino's point of view will not necessarily be 'good' for 3D printing. If there are any degenerate faces, naked edges or other issues listed, go back (ctrl-Z) and manipulate the parts until you get a result with zero problems. (The exception is 'Unused vertices' which seem to be harmless.)

    4. Delete the mesh. (At this stage, it was only for testing.)

    5. Save the altered Rhino model under a new version number, so that you can easily backtrack to an earlier stage if necessary.

    6. Return to (1) and repeat until the whole model has been successfully joined.

    7. Export the final mesh in STL format.

    8. Run a final check on the STL mesh with NetFabb Studio Basic (free software which can be downloaded from: http://www.netfabb.com/stl_repair_fixing.php). (I do not recommend that you attempt to fix a faulty mesh with NetFabb, though – better to go back and fix the original model in Rhino.)

    Hope this helps.

    Last edited: Mar 3, 2012
  14. aphollis
    aphollis New Member

    this seems overly complicated, you don't need to convert to mesh within rhino. work in solids with a high tolerance, and then export to stl, rhino will convert to mesh on export. you don't need to convert nurbs objects to mesh before this step.

    Rhino has lots of issues with watertight solids if you're joining and altering surfs with too low a tolerance and not being diligent about checking volume after every change, but it works fine if you stick to solids.

    Use wirecut over trim whenever possible, convert curves to planar surfs before extrusion, boolean to join or subtract and use .0001" tolerance. Every time you boolean, chamfer/fillet/whatever, run a volume check to make sure your solid is still a solid.

    i haven't had any problems, and the only mesh conversion i deal with is export to .stl
  15. billy57
    billy57 New Member
    Thanks Aphollis, I realise that, but the reason I take this convoluted route is just so that I can keep checking the mesh along the way. This is just for testing purposes - I don't keep the intermediate meshes. Your checking volume method seems to have the same effect. .

    I generally stick to solids, but I still encounter problems with STL exports if I don't check carefully. Thanks for the tips about high tolerance, etc.

    Last edited: Mar 4, 2012