How to create holes on a hemispherical surface?

Rhino Rhino for Windows
1

I’m trying to model a colander / kitchen strainer and I need to create a large number of holes in a pattern on a hemispherical surface. Can anyone suggest the best approach to dealing with this in Rhino 5 ? Any advice would be most appreciated.

Cheers,

Joe

2

Hi Joe,

Assuming that your colander is modeled in XY space around the Z-axis:

  1. make sure that the sphere of the colander’s interior is centered at 0,0,0
  2. create a rod of the correct diameter that passes through the shell at Z 0 at the X-axis.
    This is your negative for later Boolians
  3. rotate/copy the rod on the Y-axis at whatever degrees you like, as many times as you like.
  4. group the approved rods (the ones you like)
  5. rotate/copy the entire group in the same manner on the Z-axis.
  6. Boolean difference with the rod groups as cutting solids.

This will yield a standard-spaced pattern.
If you want to add artistic flair, _DeleteHole to achieve whatever pattern you like best.

3

Many thanks !

Joe

4

I did basically the same process with an extra step.
I assumed that the holes should be perpendicular to the surface.

1 I created the hemisphere and drew a quarter circle to match the radius.
2 I then drew a line of the same length as the arc.
3 I arrayed my cylindrical tools (to be used later for the boolean difference) along the line.
4 I then distributed the cylinders along the arc using “Flow along curve”. (check out the “Rigid” option)
5 Then grouped all of the resultant cylinders except the one pointing straight up
6 Then created a circular array
7 Grouped all of them
8 Did a shell on the hemisphere.
9 Finally did the boolean difference

It’s important to exclude the one cylinder in step 5 as you’ll end up with multiple copies in the exact same place and this in turn will cause the final boolean difference to fail. This should work even on a non hemispherical base shape.

Steve

col1.png1146×720 387 KB

5

Hey Steve,

Perfect, just what I am after.

Many thanks for your help !!!

Cheers,

Joe