IGES integration

Patis
2010-07-12
2013-04-22
  • Patis
    Patis
    2010-07-12

    BRL-CAD can work with iges. I've got a summer project to make my professor's lattice-boltzmann solver incorperate irregular meshes. To do this I was planning on making iges models and then try to transform them via a jacobian into a box. I was hoping that someone here would have an idea on how I could manage this or something similar to solve my problem like perhaps just adding the ability to read the iges. Right now his program reads where walls are and he has it set up so that there is a wall at x = 0 and x = 5 etc.

     
  • Sean Morrison
    Sean Morrison
    2010-07-12

    Your question as stated is pretty ill-posed to be able to suggest anything useful.  IGES is just an export format, which is inconsequential to what you do with the data once read into memory.

    The only suggest I can made would be to use our existing iges-g importer to get data into BRL-CAD format as an n-manifold polygonal mesh geometry (nmg).  Then you could write code that processes nmg data and incorporates his solver for manipulating the mesh.

    That way you don't have to really worry about storage formats such as IGES.  You'd just deal directly with geometry structures in memory, which would be automatically provided by BRL-CAD's libraries and geometry API.

     
  • Patis
    Patis
    2010-07-12

    Sorry for not stating my question very well. I was using iges to export from solidworks because it was the most widely used 3d cad format that I'm aware of.

    How would I go about modifying the data and is there anyway to just use a library from brlcad rather than run it as another process? I know that my professor didn't want me to use any extraneous programs since it's often difficult to get them all to mesh well.

    Would it allow me to get x,y,z coordinates of the nodes because his code currently works with ascii like x = 1, y = 1, z = 1, vel etc. I need to be able to turn the mesh into something like that.

    Thank you for your time. I've been trying to solve this for weeks now and haven't been making much progress.

     
  • Sean Morrison
    Sean Morrison
    2010-07-12

    You could certainly just use BRL-CAD's libraries to do most all of the processing.  If all you care about is xyz data for the polygons, though, just pick a simple format for export from Solidworks.  The STL and OBJ text formats come to mind.  They totally suck for actual CAD, analysis, or design work, but are great for simply representing a basic polygonal mesh.  Data is dumped out as simple vertices and faces.

     
  • Patis
    Patis
    2010-07-12

    I'll look into that.

    My last question(for now): In your opinion do you think it would be easier to transform the mesh into computational space or to modify his code to use a library to read the mesh itself? I've not actually looked at how his solver works because I was doing the former and everything I was doing was going to be pre or post processing. To visualize what is going on he uses techplot after he solves(trying to give any information that may be relevant).

     
  • Sean Morrison
    Sean Morrison
    2010-07-12

    No way to answer that without looking at his code.  Our developers, myself included, are certainly willing to help if you attempt to make his code work with BRL-CAD's libraries or if you use BRL-CAD code as a starting point.  Otherwise, it depends on too many factors, your experience notwithstanding.

     
  • Sean Morrison
    Sean Morrison
    2010-07-12

    MGEDRC_HEADER should be in the file.