When I lent my services to a collegue who was working on a film about 12 years ago, I was introduced to the world of cnc. I remember watching this huge machining centre milling out a slab of mdf and turning it into a fantastic set of gears. I knew that it would have taken me hours to achieve the same thing with traditional power tools. I decided then that I would invest in a cnc router for my own business Oxenham Design. At that time I could turn on a computer, but even to check email seemed like a crazy set of operations. I persevered and learned every piece of relevant software I could get my hands on. I am now fortunate enough to be using Vectric's ASPIRE software, and Techno cnc routers, which has helped us to create some amazing projects, both in part, or in full. I thought that this blog would be a great place to share "behind the scenes" adventures with the software, materials and equipment we use, as well as the projects we build.

Monday, 30 April 2012

No wheels on this car!

I worked most of the weekend getting the roller coaster car framework built. This was pretty simple as the work had already been done in the computer. I was supplied the size that the car needed to be already, and they would have spent a great deal of time on sizing it. When I was modelling it, I just used the dimensions supplied. With the computer model ready, and signed off on, I was able to extract the pieces I wanted from the model, and convert them to usable cut files in Aspire.
I find that Aspire, Corel Draw, and Hexagon work VERY well together for us. I saved the extracted geometry out for import into Corel, where I would get my usable vectors from.

Once imported into Corel, this is what I had. Notice that the corner rads are faceted. I could have pulled the curves from Hexagon, and imported them as AI files, but the faceting would still be there.

So to get good clean vectors, I simply had to draw over the outline with new vectors. This allows me to get smooth rads on all the corners. And as the model was draw at real size in Hexagon, there is no worry that the sizing will be different.

I made the model with the side panels being 2.25" thick. Using the vector file I created, I was able to offset the shape inwards to give me my top curved thickener piece. For the long flat runs, I cut 3/4" MDF into 1.5" strips. The curved pieces would get 2 layers of 3/4" making up the 1.5" to work with the strips. The skins were 3/8" MDF to be strong, yet lighter than solid MDF would be. The whole thing is going to come apart so it can flat pack into the van for delivery.

 The car parts are all built and have a coat of sealer on the raw edges. We got another last minute job today which should be fun. An oversized alien brain in a bell jar. This shoots on Thursday, the same day the roller coaster car shoots. Thankfully they are both shooting at the same studios, although its for something completely different.

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