Boolean question about workflow (user error)

Rhino
1

Hi,

I used the boolean two objects commend which was a ring with 4 ribs. I made the ribs and then I used the boolean command to attach them to the model. I issue I have encountered I have had before, so I am hoping to get some direction so I can correct my workflow.

Pic of the model with the ribs attached to the center round ring is what I need help with. If the pic.

Screenshot 2025-11-18 174658
Screenshot 2025-11-18 1746581920Ă—804 238 KB

When I zoom into the intersection you can see at the bottom of the rib it looks fully attached, the line in the ring is broken indicating integration of the solids. But a the top you can see the line in the ring is not broken and you can still see the tine I used to create the rib. I created the rib as planer curves, made a surface, then extruded the surface straight into a solid. But for some reason at the top the model did not boolean correctly and if I go to put a fillet on that area it does not work.

Screenshot 2025-11-18 174901
Screenshot 2025-11-18 174901729Ă—646 84.9 KB

Hopefully this is something simple? I just am not sure why I get this result.

TIA

Dan

2

I suggest you forget about booleans. They just
encourage you to make poor decisions.

For instance why are you making the ribs and ring with goal of boolean them together?
Wouldn’t it make sense to make the ring and rib shaped curves and extrude it all together?

You will model stuff like this more efficiently if you learn to do it without booleans.

3

Lay off the booleans and try getting used to using Rhino’s NURBS surfaces, trimming, and filleting tools. You will not run into the “boo” in booleans ever after.

4

Can you share the file?

5

Hi @Danf
Hard to tell from just a picture, but if the faces are planar and things are otherwise precise (in this case, if the ribs and the ring are the same height), give MergeAllFaces a shot.
HTH, Jakob

6

vacuum pod.3dm (643.6 KB)

7

I could have made the ring and the ribs as one solid but at some point I need to attach them to other solids. Are you suggesting use Union or something other than the boolean commands?

8

Thanks, will give it a go.

9

Thanks, the MergeAllCoplanarFaces worked all edges did not do anything.

10

I see there is another issue with using the blend fillet command on the inner holes. One edge will not blend, seems like the boolean command again has caused me an issue? I will try the model in nurbs…

Screenshot 2025-11-19 083012
Screenshot 2025-11-19 0830122043Ă—1145 113 KB

11

I am suggesting that booleans are not magic.They do nothing that you can’t do yourself .

I’m suggesting that if you learn to model your solids without using booleans you will become more proficient, because you will understand what a boolean is doing (or not doing).

12

It always starts with the curves check the curves

If nothing there then booleans don’t always work

Next you can try is trim

I don’t discourage using the boolean tools depending on what it’s for but this is a perfect opportunity to problem solve with other methods

From experience try to avoid boolean anything complex in one go and always inspect the results after.

Even if booleans have become better in Rhino it’s still not perfect.