3D Cad (Lesson 101)

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by superjacent, Jun 19, 2009.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Feb 9, 2012 #181

    Wagy59

    Wagy59

    Wagy59

    Well-Known Member

    Joined:
    Nov 25, 2011
    Messages:
    270
    Likes Received:
    5
    Location:
    Farmers Branch, Texas
    FYI...I'm not really disagreeing or agreeing..I'm sorta sittin here pondering it all...I admit, I kwow lots and lots of people who have used autocad for well over a decade and some for 2 decades and some of them do some pretty advanced stuff, but not a one of them can even come close to producing the kind of 3d drawings like the airplane I'm working on...It really doesn't seem that difficult to me to do it and I'm pretty pleased with being able to pull the information I want out of it...I think if a person has some experience with it and access to autocad, by all means use it..I admit AutoCad isnt easy to learn..Once you learn though, you can produce vast amounts of work quickly...But you wouldn't believe how many people claim to have 2 years of college in autocad with and Associates Degree and can barely draw a line with it


    You mean THIS button?....Sorry guess I'm too dense to realize people get all wiggly about forum clutter
     
    Last edited: Feb 10, 2012
  2. Feb 10, 2012 #182

    Inverted Vantage

    Inverted Vantage

    Inverted Vantage

    Formerly Unknown Target

    Joined:
    Jun 20, 2008
    Messages:
    1,116
    Likes Received:
    32
    Yea that's pretty much what it means. I don't know that much about your intelligence but most people (home users, at least) that I know of do not use AutoCAD for what you're using it for; more than that, most people never want to. I can make the geometry that you're making in other software - and I would never want to do it in AutoCAD. Just because a ton of big companies use it doesn't mean it's advanced; indeed, it means the opposite in a lot of cases. Large companies with lots of legacy projects have huge difficulties in transitioning to new software, especially if that software isn't backwards compatible with their old files.
    The only people I know of that use AutoCAD for personal projects are ones who've learned it way back when and managed to get good enough at it to continue using it in the future, and haven't really tried to get much good at anything else. That's a lot of suppositions about a lot of things though; it could be there are a few users out there (perhaps such as yourself?) who have tried other software and found AutoCAD preferable.

    Also, there is an "edit" button if you want to add to your posts without posting a new one. It tends to clutter up forums to have someone post multiple times in a row. :)
     
    Last edited: Feb 10, 2012
  3. Apr 29, 2015 #183

    AVI

    AVI

    AVI

    Well-Known Member

    Joined:
    Feb 25, 2003
    Messages:
    524
    Likes Received:
    50
    Location:
    Banff, AB
    Re: Rhino3D Help

    After many years of false starts, I'm finally getting into Rhino3D ... yes, why it took so long is ...

    But better late than never. What I'm attempting to do now is to add the sandwich thickness to an outer fuselage shell.
    For some reason, it was not possible to extrude the outer surface, so what I ended up doing was to extrude the perimeter curves the thickness of the core,
    then create a surface from the extruded curves. It's kind of like the thickness of the core was formed along the four sides then the inner surface was formed.
    I believe that's how I managed to get it done.

    As can be seen in the screenshot below, this worked, but at the same time, it did not work. The forward face is not perpendicular to the centerline, nor is the aft face.
    The edges of the core angle inwards, obviously due to the manner in which the curves were extruded at a 90ยบ angle.

    There has got to be a correct manner in which to skin a fuselage. How is it done? Is there a skin command?


    HBA5.jpg
     
  4. Apr 30, 2015 #184

    Dana

    Dana

    Dana

    Super Moderator Staff Member

    Joined:
    Apr 4, 2007
    Messages:
    8,685
    Likes Received:
    3,063
    Location:
    CT, USA
    It's been years since I used Rhino so I'm speaking in general terms, but "extrude", at least in the software I use nowadays, means creating a solid from wireframe curves (or, as you found, the edge curves. If you already have a surface, look for a "thicken sheet" function or create an "offset" surface.

    But either way, if the offset is, as it usually is, perpendicular to the surface, the resultant edges won't be perpendicular to the centerline. To get around this, extend the surface edges, do your offset and then trim them back to a plane perpendicular to the centerline.

    A better approach might be to create a lofted solid, not surface, then shell it to the desired thickness.

    Dana
     
  5. May 8, 2015 #185

    AVI

    AVI

    AVI

    Well-Known Member

    Joined:
    Feb 25, 2003
    Messages:
    524
    Likes Received:
    50
    Location:
    Banff, AB
    Got it figured out ... maybe not the fastest way to do it but it works.
     

    Attached Files:

Share This Page



arrow_white