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    Open source design

    A spox hub. It's pretty close, anyway. Still trying to get the hang of my digital caliper (available at any hardware store.)

    If anyone wants the google sketch up model file, I'll give it to you under the LGPL.

    That means, you're free to do whatever you want with it but you need to send changes back to the original author -me.

    Let's get a discussion going about building, sharing and licensing cad drawings to create a repository of accurate 3 D wheelchair parts.

    We're all getting screwed at some level of the medical supply: complex. At the very least, building a repository will allow us to create pretty pictures with an accurate numbers and minimize the damage that the illiterate schmucks who populate DMEs can do.

    Here's how you get started…

    1. You say to yourself, "if that asshole can do that, I definitely can do it." :-)

    2. Download google sketch up. It's not just free, it has the best tutorial videos out there. The interface is intuitive. Contrast that with Blender which is also free but it is really hard to learn. Contrast both with the AutoCAD which is available only to people with money, pirating skills and an engineering background. The entire point of this exercise is to open up access to wheelchair design. There's no need to upgrade to the paid version of sketchup. Only if you're feeling magnanimous to google. You can also send me money if you're feeling magnanimous. :-)

    3. Watch the videos. It took me a month to go from the first picture of a backrest assembly which has absolutely no relation to physical space to the hub drawing which is highly accurate and ready to be fabricated if I desired to do so. You will need to practice. I'm at the point where I wrote voice macros to handle selection, orbiting, panning and other common tasks. You'll definitely get there.

    4. Practice and post for others to see. The mere fact that others will judge you is a very strong motivator for learning to do things right.

    So here you are at the water. I can't make you drink. I can only tell you that it's good and you should try it.

    I will post the SKP file if there's any interest in this thread.

    I just found this program a few nights ago and thought it was cool, the only problem I can think of is don't you need the pro version to output something that is ready to mill or can your machine shop take file made in the free version and run them in autocad or whatever they use? I do think its a good idea other than that question.
    c3/c4, injured 2007


      There is a DWG plug in:

      If that doesn't work, I will look into Blender again.

      That said, I think the overwhelming majority of these images will be for communication, not necessarily fabrication. Google has a shallow learning curve which makes it perfect for the task.


        Great thread! I have been putting off the mechanical hardware design on my project, but this has me excited. Why no Linux version of sketchup?



          Have you tried running it in wine?

          People were successfully doing that as of version six.

          It does bring up another question:

          Do we standardize on an application or do we standardize on a file format?

          I'm leaning toward standardizing on an application because as more people learn and the library of components grows, making video tutorials benefits the greatest amount of people.

          If we standardize on a format, some people will be needlessly left behind. That's different from "some people are hopeless" which happens quite often in explaining how to do things. Some people will be trapped between learning multiple ways of doing something.



            Browse this page to start discussing the licenses we should use for models. Creative commons might be the best.

            Moving on… This file requires google sketch up. Use the google to find it, download it and install it.

            This is my ABS foot plate on my TI ZRA 21706.

            It is seven by five inches for the metric impaired.

            I wanted to create a file where the width and depth could be adjustable as components without altering the position of the screw holes.

            Adjusting the depth is not a problem. You can go from 5 inches to forever under your chair. Adjusting width, however, won't work without warping the model.

            The distance between each screw hole center is shown in red. The green zone is where there is no arc in the model to warp any width adjustment.

            This footplate would be a good start to discuss standards.

            Two things need to be standardized for all foot plate dimensions:

            1. The arc in the corners. The arc should always start and stop at N by N mm.

            2. The screw holes should be within the depth boundary of the arc. Shown in green.

            Hope that gives everybody, including the medical cartel, an idea of what I'm pushing for. It's not evil incarnate. It's better communication and engineering.
            Last edited by radio_buddha; 11 Oct 2010, 11:58 AM.


              Have a complex woodworking project for which I want to create plans. Remembered this thread. Downloaded Google Sketchup and have explored some of the tutorials. It is intuitive, but still requires study and practice to acquire minimum useful competence.

              Thanks, RB, for making me aware of this free, powerful program.

              "We have met the enemy and he is us."-POGO.

              "I have great faith in fools; self-confidence my friends call it."~Edgar Allan Poe

              "Dream big, you might never wake up!"- Snoop Dogg


                The plethora of videos, tutorials and the user base should lower the learning curve considerably.

                Good luck with your project.