Solid Cylinders / bars - How to create?

Forgive what may deserve the “silly question of the day award”, but I am new to Rhino3D.

I can create a square slab and show round holes in it;

I can create a cylinder and show a hole plunged into the side of it;

… but I can’t for the life of me figure out how to put holes through a solid round bar. I need to show a 98mm DIA by 11mm high steel flange. That flange has 4 OFF 8mm DIA holes drilled right through it (face to face).

Any pointers please… Ive tried all sorts and can’t figure it out!


Hi John- you can use an array of cylinders and BooleanDifference them from the flange, or use RoudHole to get the holes in the flange. Attched is a way to do this with just combinations of cylinders. There are other ways to approach it…

Flange-Holes.3dm (106.5 KB)

Thanks Pascal,
The flange you crated with 4 OFF holes in it is almost exactly what I need to produce, except I need another identical flange at the other end of the collar.

I figured out how to get the holes in a square slab using “Round Hole”.

Ive also figure out how to create the smaller DIA tube and I can put "Round Hole"s in that too (within the wall thickness).

To get the “round slab” WITHOUT a hole in the middle (i.e. not a tube) I tried to create a tube with a wall thickness half of the diameter, but the round holes won’t go through it when I do the same as I did in the square slab… This makes me think Im not creating the base solid correctly.

In an idiots guide fashion, could you please expand on how to create a round slab of solid, in my case I need 98 DIA by 11 high. I should then hopefully be able to get the holes in it.


Hi John- use Cylinder, Solid=Yes. That is what I made my example with. Another valid approach is to draw the cross section of your pipe with the flange etc- just one one side and Revolve it on the center line.


Or draw your slab with bolt holes (blindflange?) in 2D, using “Circle”, then extrude the lot to the required thickness with “ExtrudeCrv”. Tick the box “Solid”. Make sure your 2D circles are on the same construction plane.

Genius! I never thought of that.

All sorted now. Many thanks.


Can you show us a picture of your result, just for fun?