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How to turn mesh to part or some other solution

BORN_TO_RUNBORN_TO_RUN Member Posts: 1 EDU
I recently took a model off of thingiverce to incorporate it into a design that I had made. I imported the model into Onshape and found that it was a mesh. My plan had been to get the two separate parts and then bind them in assembly but found that I could not do this because meshes cannot be used in assembly. I am fairly new to 3D design and Onshape and didn't know if there was a way to do this in Onshape or some other software. Also if I was able to combine them would there be an issue with not being able to print a design with mesh? Thanks!  

Best Answer

Answers

  • carl_von_ayrescarl_von_ayres Member Posts: 16 ✭✭
    I believe powersurfacing app in the app storr can handle meshes, convert them and push it into onshape. Haven't do this myself though.
  • philip_thomasphilip_thomas Member, Moderator, Onshape Employees, Developers Posts: 1,381
    STL is an end result - trying to do anything with STL is a reverse engineering process and an imprecise one (accuracy has already been lost due to the faceting process).
    STL is primarily used for 3D printing and Thingiverse is a great collection of ready to print stuff. None of the models on that site are 'b-rep' (boundary representation). 'B-rep' is the representation that professional grade 3D solid modelers read, use and write.
    Onshape supports STL import to allow for space allocation in designs and to reference while creating new parts.
    While there are 3rd party softwares that will 'convert' STL to b-rep, the performance of those when imported into Onshape is terrible because of the enormous number of faces and edges (100 x that found on a 'normal' model).
    There are some very good public repositories of b-rep models (check out grabcad.com) and of course, Onshape can make STL from any of them.
    Have fun! :)
    Philip Thomas - Onshape
  • GWS50GWS50 Member Posts: 220 PRO
    I have a method for this, but it is not practical to everyone.......
    I use scan data from sculpts to create mechanical designs so I'm always trying to get STL's into a workable form.....it is not easy!!
    Use Meshlab (open source software) to decimate your STL to 5000 faces, import into Vectorworks and use the 'convert to generic solids' and then export as Parasolid XT which creates a part in OnShape. You can use 'Instep' to do the conversion (into a step file) but it doesn't always work, infact I'm not sure why the VW solution works but it seems to be something with the number of faces/calculations that CAD programs will handle as a solid.

    I'm not a computer buff but I have found this method through many late nights!! I'm sure there are other methods but as I mentioned before it is not an easy process....if someone comes up with a solution to this they might make a bob or two!!
  • isaac_fifeisaac_fife Member Posts: 2
    How do you use the mesh as a reference geometry though? I don't think that was explained and I can't figure it out.
  • geoffrey_2geoffrey_2 Member Posts: 9 PRO
    How do you use the mesh as a reference geometry though? I don't think that was explained and I can't figure it out.
    This is where I'm getting stuck, too.  I have no problem with using the STL as reference geometry, but it certainly would be nice if I could use tools like the tape measure to actually get measurements so that the "reference geometry" is more than just a direct visual reference.  But, right now, you cannot select a facet of the STL to get a measurement relative to another facet.  It simply selects the entire mesh object...

  • geoffrey_2geoffrey_2 Member Posts: 9 PRO
    How do you use the mesh as a reference geometry though? I don't think that was explained and I can't figure it out.
    This is where I'm getting stuck, too.  I have no problem with using the STL as reference geometry, but it certainly would be nice if I could use tools like the tape measure to actually get measurements so that the "reference geometry" is more than just a direct visual reference.  But, right now, you cannot select a facet of the STL to get a measurement relative to another facet.  It simply selects the entire mesh object...

    FYI, I discovered that I could use tape measure, but only if I selected vertices, not facets or edges.  The ability to select facets and edges of STL meshes would be a great improvement for making STL imports more useable.
  • billy2billy2 Member, OS Professional, Mentor, Developers, User Group Leader Posts: 1,665 PRO
    edited January 8
    I have found that "FreeCAD" has the ability to convert a mesh into a step file and then you can import these into an Onshape assembly. 

    meshes inside an assembly:


    I've spent a lot of time trying to clean up the mesh and produce some surfaces but nothing seems to work.

    I've issued an IR to allow mesh data types & images inside an onshape assembly.

    Please vote this up:
    https://forum.onshape.com/discussion/13364/meshes-in-drawings-assemblies



      
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