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.

Friday 2 September 2011

Let the modelling begin!

We delivered the columns and header today. I had to cut a few pieces of acrylic that would become the edge to the simple table we made. These edges stick up around 3" to prevent the motorized robot toys from committing suicide on to the floor. We wrapped the stuff up, and put it in the van and away we went. We got back to the shop around 3 and I got right to work on the Louie model. I had spent a little time last night working on the plane, but it quickly occurred to me that it would be best just to model the plane from scratch. The reason for this was that there was a baffling amount of geometry in the imported CAD file. When I exported the file out as an OBJ surface model, it looked good, but there was 2 surfaces for each inside and outside surface on the model. This meant to modify anything, I had 4 surfaces to deal with, and each surface was so close to the other ones, it took forever just to remove small sections. The other reason was that after I had detached the parts I wanted off, the model had so many holes in it, it looked like it had been thrown in a blender for a while. Even if I had persevered, I still had to deal with the pocket holes for the screws, etc. It would be way faster to start again. Just the plane though, I will change very little on Louie himself. I was able to take the CAD file, remove Louie and model the plane to a 2D outline image for the front/top/left and back view. With this outline image, I opened our other 3D software package, brought in the 2D images, and set them up as modelling blueprints. This gave me an un-distorted plan view from which to start modelling from.
It looks a little weird at this point, but the three views I'm interested in all line up perfectly.

I started with the nose cone of the plane, creating a cylinder and adjusting it to the image in all 3 of the views.
I then just started a new cylinder, and followed the contours of the plane images.
It doesn't show in the screen grab, but I actually have 3 simultaneous windows open, showing me the different views I need all at once. This allows me to tweak a portion and see it update in all the windows. When the fuselage was finished, I started on the wings. I used the blueprint as a size guide only.
Because our model will be HUGE compared to the toy, I felt that the small little wings lacked any sort of resemblance to a plane. I added some ribbing to the model to give it a stretched canvas kind of look.
Next was the rudder and tail fins. I didn't do much different than the drawing on these parts, except to shape the profile a little more like a wing shape.
Finally I closed off the nose cone with the recess like the toy has. On the toy, the engine parts are printed on a sticker and stuck in there, We will model a very simple rotary engine with a clear disk representing the 'spinning' propeller.

Here is the finished plane with the imported Louie model set in place. You can see all the dark grey lines on the plane and Louie, this is the wire cage for the model. By re-modelling the plane, you can see I have cut the geometry down by at least 90%. This will make it VERY easy to section the plane up for import into Aspire. for machining.

8)

JO

3 comments:

  1. that is simply amazing!

    ReplyDelete
  2. That is really cool! I can't wait to see it all completed. What modeling software did you use to model the plane?

    John

    ReplyDelete
  3. Thanks guys! We use Daz 3D's Hexagon modelling software. The learning curve was a little steep, but I find it way more intuitive than Maya, Max or Modo.

    ReplyDelete