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Thread: Sizing Model

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  1. #1
    Join Date
    Jun 2012
    Posts
    393

    Sizing Model

    I have been asked to cut a model. I was sent the model in Obj format. I had to remove a part of
    the model and cut the rest. It comes into Bobcad way to big. When I use the material wizard to
    create a box it creates a box about 2" square way below the model and to the Z plus of the model.
    Lets say I want to cut a 7" 3D model how do I size it and fix the problem. The model is also not oriented
    correctly on the X,Y,Z. Do I need to ask the model maker to do all of this. Lost in CNC land. No Zombies.

    Here is the BBCD files if it helps.

    Don
    Attached Files Attached Files
    The time has come the woodworker said to speak of many things. 0f routers and Wood , chips and paints and stains and CNC and other things.

  2. #2
    Join Date
    Aug 2012
    Posts
    621
    First, I'd use the Rotate function to get it oriented how you want it. In the [Origin] section of the Rotate tool, check <Enter> and leave all the numbers at the default of 0.00. That will make the Origin your rotation point. If you want the body of the model in the XY plane, that would mean a +-90 deg rotation around the X axis, for instance, with the negative value putting the head toward the Y+ direction.

    Once you've rotated it to the orientation you want, you can [Translate] it to the position you want it at, either numerically, or using the <Drag> tool. Then use the <Scale> tool in the [Translate] box to scale it to your desired size. After that, you can draw a rectangle around it and use that to define your stock.

    Luke
    "All I'm trying to find out is the fellow's name on first base" -- Lou Costello

  3. #3
    Join Date
    Sep 2012
    Posts
    1195
    Can't look at the file right now, but it' pretty easy to scale the model. Right click on the object and select "entities summary" (if memory serves). This should bring up a window that gives the max and min dimension/position of the selected object. Note down the numbers.

    If you know what the desired size is, use a calculator to divide that number by the current size for that axis. This is your scale factor. Use the "Translate" function and click on "Scale". Enter the scale factor and perform the translation. You can also reposition the object to the origin at this point as well, but it is not necessay for the scaling to happen.

    Hope that helps!

  4. #4
    Join Date
    Jun 2012
    Posts
    393
    Thank again. I just learned a lot about the rotate tool and preview. I did get the model in a good position for cutting. Now to figure out how to cut it. I have 3 axis so undercutting is out. I think maybe cutting half of the model then flipping the material and cutting the Back side. do this for 2 half's and glue the 2 half's together. It is an animal with wigs. Any other ideas ?

    Don
    The time has come the woodworker said to speak of many things. 0f routers and Wood , chips and paints and stains and CNC and other things.

  5. #5
    Join Date
    Apr 2009
    Posts
    3376
    "Any other ideas ?"


    Learn to fixture real,real good.

    Learn the UCS,learn the UCS,,,,,,,,

    Become proficient in CAD/CAM

    I hate to discourage you,BUT,,you ought to get the hang of easier stuff for a while.You need to get a good understanding of Machinist skills,CAD and CAM.
    IMHO,a need for the Pro multi-axis tool paths are needed also.
    This is just a wee bit on the hard side of making.

  6. #6
    Join Date
    Aug 2012
    Posts
    621
    Your plan for doing it in two halves sounds like a good one. I assume you're doing the wings separately? I like to jump in with both feet, but jrmach has some good points. Cutting full 3D pieces will seem a ton easier to you after another few months of using the software. Like most things, there's really no substitute for a strong set of basic skills.

    I just clamped up a walnut jewelry box with some complex hidden joinery, and a 9-piece panel-and-frame lid. I originally drew it about a month after I started out with BobCAD but it took days of drawing, and was a real bear to get the parts to fit up properly. Took far too much fiddly hand work. I recently went back to the design, threw it out the window, and re-drew it from scratch in about an hour. The thing fit like a glove the minute I pulled it off the table.

    Luke
    "All I'm trying to find out is the fellow's name on first base" -- Lou Costello

  7. #7
    Join Date
    Jun 2012
    Posts
    393
    A also agree with Jrmach. These are the things I want to be able to do. In a fashion. I want to do Heraldry and 3D things. I hope I can find and alternate way then 4th axis.

    Thank You
    Don

    See next post for something I can really cut.
    The time has come the woodworker said to speak of many things. 0f routers and Wood , chips and paints and stains and CNC and other things.

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