Trouble with understanding the filletedge-command


Hi everybody.

I’m a beginner-user of rhino and I’m having some problem understanding how the rhino-software reasons.
Right now I’m trying to model a simple cylindar container. I would like to rapid-prototype it in a 3d-printer and therefore I’m going for solid-modelling instead of surface-modelling.
As you can see in the images I started of by creating a tube with the correct dimensions. Thereafter I made the bottom-part by using the cylinder-tool. In the next step I joined these parts using booleanunion and created the inner 5 mm fillet. The problem arises when I’m trying to use filletedge-command on the outer-bottom-edge. Instead of creating the desired radius Rhino creates a new 5 mm polysurface on the inside of the cylinder. And I don’t understand why, I’ve looked in the help-sections without finding any answer to rhino’s actions. I’d really appreciate some help here.

(Brian James) #2

Hi Martin,

Make sure that the FilletEdge option in the command line to ‘Trim and Join’ = Yes. If the fillet is still a separate surface there probably isn’t enough room for it to trim and join into the existing geometry.

Here’s a video I made a while back that may help as well… post the model if you still have trouble and I’ll take a look.


Thanks @BrianJ

That was a very helpful tutorial. I tried again and yes the command-bar says ‘Trim and Join = Yes’. I guess your second guess is correct: there’s not enough space to perform the action. I don’t understand why though(?) My bottom-part has a thickness of 2 mm and I want a radius of 5 - apparently a radius of 1 mm works just fine. I though that joining the bottom-part and the cylinder by using the booleanunion-command rhino would allow me to go for a bigger radius, but I was wrong. I attached my model - I’d really appreciate if you could tell me what’s wrong with my strategy of modelling this container.

Cylinder container_tube.3dm (187.4 KB)


explode the outer cylinder… delete that lower 2mm cylindrical section. use MoveEdge on the edge of the cylinder at a distance of -2… rejoin.
the fillet will work then.

likewise, you can get rid of that then use FilletSrf on the bottom cap and remaining cylinder portion… then join.


You could use just a normal cylinder, use the fillet option on the outer edge, and then use the “Shell” option on the top-surface of your cylinder to hollow out your object?