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.

Thursday, 2 June 2011

A revolve style tutorial

Before we build on the banner tutorial, I thought I would add a small tutorial on spinning a relief. I don't know if anyone else has done this yet, I haven't seen anything on this, but that doesn't mean it hasn't been done either!

 Revolving simply means to spin a profile in a circle, similar to turning a "bowl' style shape on a lathe. This is quite a bit more flexible than the "create shape" function in terms of actually using an exact profile. In this tutorial, we will create a crazy rim for a tire. Again, as always the instructions fall BELOW each image.

Firstly, open a new project with a size of  20" X 30" I chose a thickness of 3". Also set the 'Modelling Resolution to HIGH(3X)

The first step now is to draw our outside rail. Use the circle tool to create a circle 16" in diameter. Then hit the highlighted "CENTER IN MATERIAL" button. This makes all of our alignments easy.

Then switch to the "NODE EDITING" tool in the drawing tab. select the middle left node of the circle and right click. From the fly-out menu, select "CUT VECTOR" You'll notice that the node has changed to a green colour. What this does is breaks the closed circle into an open circle. This becomes our 1st drive rail for the "2 RAIL SWEEP" function to use.

Now we want to "CTRL-C" then "CTRL-V" to copy and paste the same circle. Switch back to the "SELECT" tool and select the circle. Then select the "OBJECT SIZE" button from the 'EDIT OBJECTS' tab.

This brings up the "EDIT SIZE" dialog box. Enter a tiny value of .005" If the "LINK XY" check-box is checked when you hit apply, you should see the X and Y values become the same. If not, just enter the same value of .005 into both boxes. You now should have a nearly invisible circle in the center if the page. Go ahead and close out the dialog box.

Select the "RECTANGLE" tool from the 'DRAW VECTORS' tab. Draw a rectangle close to the circle and enter a value of 8" wide and a height of 4".

Now we switch back to the "NODE EDITING" tool and select our rectangle by clicking on the very bottom line of our rectangle. Now we right click and choose "DELETE SPAN" from the fly-out menu. This gives us our open cross section for the "2 RAIL SWEEP"

Now we get to define the cross section of our overall rim profile. Have fun trimming and joining vectors. Whatever shape you can make. Just remember to leave the vertical lines alone on this one.

This is the profile I came up with.

Now we need to switch over to the "MODELING" tab. Just double click anywhere in the empty blue space on the left, it should switch over for you. Then we select the "2RAIL SWEEP" icon which looks like a leaf and is found under the 'modeling tools' section. Now we shift select our 1st and then 2nd drive rail, and lastly our cross section. Remember it's a 2 rail sweep, so we need to select our 2 rails first!
Now, if your profile sweeps your cross section in reverse of what you were thinking, undo the last 2 rail sweep and select your drive rails in the opposite order, always selecting the cross section last.

TA-DA! We have created a revolved shape using the 2 rail sweep. Perfect for our rim model.

Lets add the spokes! Or more precisely, removing the spaces between them.
Go ahead and draw the vector that will become the space between the spokes. Make sure that your final shape is where you think it needs to be in relation to the rim shape. When that's done, we want to select the "ARRAY COPY" button found under the 'edit objects' tab.

After the dialog box opens up, we want to select our newly drawn spoke spacer. Select the "CIRCULAR ARRAY" button, as we want to copy these around the inside of the rim.
As we centered our rim in the center of our workpiece at the beginning, (my workpiece was 20" X30 ")
I have set the "centre of rotation" at 15" and 10"  Check the 'rotate copies', as we only drew 1 shape, and put in the number of copies you want. I chose 5, but you could have more or less, whatever you would like to see.

Now you should have 5 shapes representing our spoke spacing.

Let's swithch over to our 3D modeling tab. Double click anywhere in the empty blue space in the drawing tab. Once your in the 3D modelling tab, shift select your 5 rotated vectors and the 3D relief, hit the "clear area inside" button highlighted in red.This will "punch out" the rim with our shapes.
Looking good!

Lets add the lug-nut holes now.

I drew 3 circular vectors and a 6 sided polygon. The polygon will be our 'nut', the 2 outer vectors will be our "hole" and the small inner circle will represent our threaded "stud"

Again, we will select our grouping of circles and the polygon, and "array copy" them. Use all the same settings from when we copied the rim spacers earlier.

Switch back to the 'modelling' tab. We now want to select our 2nd largest circles and our relief, and hit the highlighted 'clear relief INSIDE selected vectors' button. This will punch 5 holes through our part.

Now select our 5 outer most circles and select the highlighted 'create shape' button.

Under our settings, we want to select the flat shape profile, and assign a height. In my case, this was 1.125" . Also make sure to select the "MERGE" button at the bottom.

This should be the result were after. A flat bottom pocket hole.

Next is to select our 5 polygons that represent our 'nuts'. Select the 'Create shape' tool and assign a height to the nuts, and use the flat profile. I chose a height of .250" At the bottom off the dialog box, make sure the 'Combine with other components' is set to ADD. This is because we want to 'ADD' this shape on top of our pocket hole.

Finally, select the smallest circles, and add a height to them. I chose .125"

 There you go! Our rim is done.

 Lets add a tire now.

 Select our outer circle we made in the beginning and using the 'node tool' drag-select our original nodes we cut apart at the start. From the right click fly-out menu choose "CLOSE VECTOR" and then "MOVE ENDPOINTS"

CTRL-C then CTRL-V to copy and paste this vector back into the drawing. If you double left click, you will get the manipulator handles to appear. If you grab the bottom right handle while holding the SHIFT key down, you can drag the circle bigger while keeping it constrained to the centre of our page. Drag it out until you like the proportion for the tire side wall width.

Shift select both our 'tire' vectors so they highlight in pink. Switch to the modelling tab and select the "CREATE SHAPE" tool. In the settings, choose the dome feature with an angle of something like 54 degrees. I chose a base height of 2", but yours might vary based on YOUR cross section you drew for the rim portion.
Lastly make sure the "MERGE" feature at the bottom is selected and hit apply. If the tire is to high or to low compared to the rim, play with the 'base height' setting to correct it.

 Now all our tire needs is some branding!

 I selected the text tool and typed out a name for our tire. Then I selected the 'TEXT ON A CURVE" tool. I set my parameters shown in the image and hit apply. Now my text is wrapped onto the tire.

 Finally, select the "CREATE SHAPE" tool from the modeling tab and select the text we created. Select the flat shape profile and add a height of .060" Make sure it is set to ADD at the bottom, as we want to add this new shape to the tire.

There you have it. A branded rim and tire. The names a little big, but there's no such thing as 'BAD PRESS"!



  1. How did you machine this?

  2. We never actually machined this part. However, I probably would use a combination of raster and offset with a few profile passes thrown in. I hope this helps!