5 replies to this topic

[sbaxton]

[I posted this also in https://www.reddit.com/r/KNEX/, but this forum seems to have more action.]

I have a small group of 8th grade students working on a K'Nex project that requires the creation of some sort of blueprints (either by hand or computer). We're looking to try building our model in a CAD program, but I've found very few good resources online. (Note, the blueprints do not have to be photo-realistic. They could even be abstract, e.g. balls and sticks in Paint.)

We've tried MLCAD, which is a bit cumbersome (as it's designed primarily for LEGO), but is potentially doable. (I found an old instructable at http://www.instructa...Model-On-MlCad/ and the parts at http://knexguntutori...x-software.html.)

I also found online https://grabcad.com/...cent&query=knex, which has the main parts individually. It seems the parts are mostly available for the SOLIDWORKS CAD program.

Does anyone have any experience or suggestions for making K'Nex blueprints in CAD?

[Ghostbuster]

I would like to recommend Autodesk Inventor for students which is a free CAD program if they sign up. They get a licence for a few years which allows them to use the professional version.

I am using this CAD software for my study and can highly recommend it.

[sbaxton]

Thanks very much for your reply.  I installed Inventor and played around with it for a bit.  Boy, am I having a hard time!

 

I've been able to import the grabcad parts referenced above and start to manipulate them in an Inventor assembly.  I'm very familiar with TinkerCAD, but am having a great deal of trouble lining the parts up in Inventor.  Even rotating things 45 degrees is cumbersome for me.  I've done some of the Inventor tutorials, but the learning curve seems very steep.  

 

In the thread http://www.sscoaster...iles-available/, alpal (the creator of the grabcad parts above) says "It is surprisingly easy to build in Inventor."  I must be missing something, as I'm having a very hard time manipulating pieces.  Alpal also says "I have also created iComposites on the ends of rods and on connectors so that I can just click and drag rods and connectors together."  

 

As you seem familiar with Inventor, do you have any recommendation as to the basics on how to move, rotate, and assemble the parts in Inventor?  Any advice about creating iComposites?

 

I also was able to import the grabcad parts into TinkerCAD, and am considering going that route.  I'm sure to have trouble when it comes time to print the blueprints, though, as TinkerCAD is very limited in what it can do.

 

Thanks for any advice/reply!

Edited by sbaxton, 08 February 2018 - 11:31 PM.

[~stεεlspectrum~]

A 3d CAD program like Inventor or SolidWorks seems like it would be great for detailed design - if you want to make a highly accurate and photorealistic model of what the KNex will look like, or need to know exactly how many of each piece you'll need. It would take a long time to make a model, but it might go quickly if alpal knows of a quick way to snap the pieces together in Inventor.

Alternatively, you could use CAD to make a simplified 3d model with common shapes instead of KNex pieces. I'd recommend SketchUp as a good starter CAD program... It's catered to non-engineers, the interface is more intuitive, and it's free!

There's also programs and websites that will allow you to make more simplified drawings of the model with 2d shapes instead of a 3d model. PowerPoint could work, though it's a bit finicky. I really like making diagrams on a website called draw.io (that's the URL).

[sbaxton]

Update:  I played with Inventor for a number of hours, but found trying to snap the pieces together using Joints/Constraints to be difficult/cumbersome.  I'm sure that's mostly due to my unfamiliarity with the program.  My hope was to learn constraints well enough to streamline them using iMates/iComposites, but the learning curve was too steep for me.

 

Instead, I went back to Tinkercad, and it's been going well.  I find the interface much more intuitive for moving/rotating/etc.  Although the pieces in Tinkercad don't "snap" together, eyeballing the connections is relatively easy and good enough for what we're trying to accomplish.  (I'm using alpal's parts https://grabcad.com/...ry/knex-parts-1, which are 1:1 scaled correctly.  Note that the yellow rod is missing from his set.  I used FreeCAD to convert the .step files to .obj to import into Tinkercad.)

 

Thanks to all to responded to this thread!

Edited by sbaxton, 11 February 2018 - 05:38 PM.

[Ghostbuster]

You could have a look at the build in tutorials Autodesk gives you. Inventor has kind of steep learning curve. Since you are interested in the blueprints I would recommend you to start from de "drawing" tutorials or the "assembly" tutorials.
 

Edited by Ghostbuster, 16 February 2018 - 10:25 AM.