Old school CAD: Cardboard Aided Design

[Ace-Garageguy]

Ever thought about building a custom car body or parts (models or real cars)? The old methods still work just as well as they ever did, and are easily accessible to backyard-shop builders. No intense computer-rendering training or multi-million-dollar full-scale 5-axis CNC tables required.

 

 

Edited September 28, 2018 by Ace-Garageguy

[cobraman]

Interesting. Did you use that method to do your 3 wheeled ( ? ) project car your building. ? Are you still working on that ? I think you were debating on a power source for it.

[SfanGoch]

Very cool and informative, Bill. It ain't hard once you try it.

[Gramps46]

Yup, works for models too as Bill says.

[bobthehobbyguy]

Bill thanks for sharing an informative video.

[Ace-Garageguy]

3 hours ago, cobraman said:

... Did you use that method to do your 3 wheeled ( ? ) project car your building. ? Are you still working on that ? I think you were debating on a power source for it.

Pretty much the same method, yes, but slightly different. And yes again. It's the first project slated to be done after I move, with a 600cc liquid-cooled Kawasaki 2-cylinder. In the last week of August, I also began talks with a supplier of 25 HP electric motors, currently used in self-launching sailplanes.

The construction method in the video should be quite familiar to anyone who's built balsa model airplanes, too.  

Edited September 28, 2018 by Ace-Garageguy

[monza77]

Now that I'm retired I would like to build some of the Can Am cars that the old Car Model and Model Car Science magazines provided plans for. The plans had cross sections of the cars that I thought could be used to make the buck. What I was wondering is whether there is software that could generate cross sections of newer cars from 3d models. If these could be made in a 3d printer, it would keep costs down, especially for larger scales. I know nothing about Cad so the info would be appreciated.

[Ace-Garageguy]

26 minutes ago, monza77 said:

.. What I was wondering is whether there is software that could generate cross sections of newer cars from 3d models. If these could be made in a 3d printer, it would keep costs down, especially for larger scales. I know nothing about Cad so the info would be appreciated.

Yes, 3D models can be used to develop cross-sections for building a buck. A board member here, Pico (Pico Elgin) has developed 3D models and printable files from sources as obscure as video-game representations of several vehicles. Generating cross-sections from a 3D model is relatively simple for someone who's familiar with manipulating the software, but 3D printing them out adds unnecessary expense.

Cross sections can simply be printed in 2D on paper (in the correct scale, including full size), and traced on to plywood or other flat stock to make the actual "stations" of the buck.

Edited September 28, 2018 by Ace-Garageguy

[monza77]

Thanks for replying. I was thinking printing it would be more accurate than my cutting it out. 

[Ace-Garageguy]

11 minutes ago, monza77 said:

Thanks for replying. I was thinking printing it would be more accurate than my cutting it out. 

If you cut carefully, you can get accuracy to a couple of one-thousandths of an inch, which is plenty close enough...even if you're working in very small scales.

Model car kit manufacturers regularly make measurement and scaling errors all over their models, probably averaging in at about one-scale-inch. This equates to 1mm in 1/25 scale, which is about .040". The typical model builder is simply unaware of discrepancies in this range.

The whole point of the thread is to illustrate that computers and CAD and 3D-printing are completely unnecessary if old-school techniques are applied with a reasonable amount of thought and skill.

HOWEVER...the thread is based on going from an original design, or something real that at least some section drawings and dimensions are available for. 

Developing accurate section drawings from 3D models is outside the scope of what's presented here, but as I mentioned, it's relatively easy to someone versed in CAD.

If you'd like to get started working with CAD, which is really helpful for anyone who makes things (whether you have the old-school skills or not...the old and new techniques complement each other), I can highly recommend the free version of SketchUp. It allows users to become familiar with working in a virtual design environment, with no monetary investment, and at their own pace.

https://i.materialise.com/blog/en/first-3d-model-in-sketchup-tutorial/

I know several people who started working CAD in SketchUp, and have gone on to do some really amazing things.  

 

[monza77]

Thanks again. 

[Richard Bartrop]

Most 3D modelling software has a function that lets you take slices out of a model.  The one I use, Lightwave, will also let you export the result in a form you can use with 2D software like Photoshop.   If you have Photoshop, I've found their ruler tool very useful for developing plans from photo references.

Inkjet printers will take very thin sheets of plastic.    DON"T put sheets of styrene into a laser printer.

Another popular free 3D program is Blender.  It has lots of bells and whistles, though it can take a while to learn.

https://www.blender.org/

Edited September 29, 2018 by Richard Bartrop

[89AKurt]

I watched the video, thank you for posting and creating this thread!  I know this is how the Italian design firms built the classics I'm a fan of.  I have not tackled a total design, but do use cardboard for mock-ups.  Current project is a conversion of a resin conversion, a Canopy Express.  I'm close to creating the plastic forms to make the vacuum-formed panels.  It's all by eye, not really accurate and to hundredths of an inch/mm, but if it looks good, I'm happy, and that's all I care about.

[Richard Bartrop]

A set of French curves are cheap, and just the thing for laying out all those nice, smooth curves.   Staedtler also makes a very nice flexible ruler for the same function.

[Ace-Garageguy]

1 minute ago, Richard Bartrop said:

A set of French curves are cheap, and just the thing for laying out all those nice, smooth curves.   Staedtler also makes a very nice flexible ruler for the same function.

Ah yes. EXCELLENT advice.  

[Spex84]

This is awesome stuff  Makes me want to design and build my own car.

When I was super-keen on drawing cars as a teen, I learned that while a French curve was good for doing dramatic, pronounced curves, the more subtle curves seen in the bodysides of many cars could be more accurately scribed with the aid of a set of "ship curves":

 

 

[Bugatti Fan]

James Dyson's team who design their vacuum cleaners and other appliances first sketch and 3D model their concepts in card the traditional way before even looking at doing anything on computer. His reasoning is that his designers get a better feel for the product by physically modelling by hand first.

[Ace-Garageguy]

Here's a shot of Brave Speedlove, standing next to the full-scale plywood mockup of his Spirit of America LSR car.

https://www.hemmings.com/blog/2018/09/30/a-chainsaw-a-marriage-and-lots-of-fiberglass-how-craig-breedlove-cleared-a-path-for-the-spirit-of-america/