Thursday June 21, 2018 at 9:21am
The World Cup is here again! The geometry of the football itself is always a little interesting. What panels make up the surface? Looking at the ball closely, I could see that it was one shape tessellated 6 times - a weird cube as it were. So, how can we model this up in SOLIDWORKS?
The World Cup is here again! The geometry of the football itself is always a little interesting. What panels make up the surface? Looking at the ball closely, I could see that it was one shape tessellated 6 times - a weird cube as it were. So, how can we model this up in SOLIDWORKS? Will we need complex surface tools? Weird lofts? No! We use a split line or two, copy a couple of surfaces and pattern, pattern, pattern.
Step 1: Draw a spherical surface section 220mm diameter.
This is the standard size of the competition ball, at least
as far as Google would tell me. I drew a
semicircle at the required diameter and created a mid-plane revolved surface
over 90 degrees.
Step 2: Create a ‘quarter-square’ face
If you examine pictures of the ball, you will see that it is
made of just 6 pieces. The faces are also rotationally symmetrical every 90
degrees, so we will start with a simple trim.
The line is just angled up at 45 degrees.
Step 3: The Split
Now comes the ‘fun’ bit. We need to create the shape for the
actual face. We only have to do a small section, but we will make sure it
matches up as nicely as we can.
We want a 2D sketch; it is a simple stepped design. I just
need to ensure that the centre line passes through the origin and that the two
shorter horizontal lines are equal. Two dimensions and we are done.
Next for the Split command - it is on the Direct Editing Tab.
We are then left with 3 surface bodies.
If all has gone well then the model should look like this:
Step 4: Thicken
We want to thicken the three surfaces. This requires three
separate operations and you need to ensure that the merge result box is kept clear. We will
then have three bodies in our part (shown in different colours for clarity):
Step 5: Move the Split Bodies
Now we need to rotate the coloured bodies 180 degrees to
form the section of the panel. The Move/Copy bodies command is also on the
direct editing tab of the Command Manager. You can choose the edge between the
red and grey parts in the centre to use as the axis of rotation.
Then we will use the Combine command to Join the bodies
Step 6: Finish the section
Now we need to finish our section, since we have a quarter
of the panel we can just create a simple circular pattern. We will pattern the
body and not the features:
Then we Combine and add a fillet to finish the section:
Step 7: The finished ball
Now we just need to create an assembly of 6 panels.
Insert the first instance at the origin and then a second
and mate in place.
We now have one third of the ball. You could repeat the last
step to add the remaining faces, but we can do it with just one circular
First, create the Axis:
This goes between the two corners of the two panels as seen
above. We can then use a circular pattern to finish our ball:
Conclusion/Penalty Shoot out
So, there we have it: the Telstar 18 Ball. If we tweak the
shell thickness we could get an accurate weight for the ball as well, or
perhaps we could use Flatten surface to find the cut shape required for the flat
leather sheet. You could also add decals and generate the image at the top of
With that done, I think I can go and watch some football...let's hope all the Home Nations
(England) do us proud!
By Gordon Stewart