Need help with boolean difference, surfboard design [SOLVED]


Hi there,

I’m working on a balsa core surfboard for a wood science and engineering project at my university. I’m currently working on a 3D design with Rhino. I’ve carved a honeycomb pattern in my surfboard but for some reasons I have 3 specific honeycomb holes that I just can’t seem to carve using boolean differences. I’ve done most of the board (100+) but these 3 holes won’t work. If anyone could give me a hand it would be greatly appreciated.

File ‘‘shortboardrhino’’

<div style=font-size:9px;font-family:Arial, Helvetica, sans-serif;width:127px;font-color:#44a854;> file backup online

Picture :


(Wim Dekeyser) #2

(it looks like there are 4 holes that did not work).
If you intersect the surfboard with one of the ‘cutters’, do you get two closed curves? You might want to try to do the manually: extract the top and bottom surface of the board; explode a cutter; trim them to each other.

Also, here are a few links:
Booleans FAQ
RH5 Help on Booleans


I noticed that on one side the intersection curve is open. I also see that there is a small gab between the intersection curve and the board’s surface. I’m having trouble cleaning it up. I don’t know how to draw a new curve directly on the surface. I can’t get the snapping to work properly. Any help would be greatly appreciated.

(David Cockey) #4

I also see that there is a small gab between the intersection curve and the board’s surface.

The intersection curve should be on the surface if the surface was used to create the intersection That gap you see is probably due to too coarse a render/display mesh. Refining the Mesh settings in Properties will probably make the gap go away. Those settings control how surfaces are displayed on the screen, not how the calculations are done.


Well then what should I do? my intersection curve is open. When I try to close it with a curveonsurface the split doesn’t work either. So far this is where I’m at but I can’t get the rest of it off.

(Joaquin Laborda) #6

If you send the model you might receive better advice.



Here it is let me know if it works

(Joaquin Laborda) #8

Thanks for the model, it doesn’t seem like an easy solution. You may have found a bug.
One thing I noticed is that you have your normals inverted, this will give you in the case that booleans work, a wrong result.

(Joaquin Laborda) #9

shortboardrhino_fixed.rar (2.1 MB) I found the issue, you have one surface with a complex structure that is causing a dificult to find intersection.
Rebuilding the surface with just one vertex at the edge lets you create subtractions without problems.

The model:

shortboardrhino_fixed.rar (2.1 MB)




Joaquin thank you so much for your help. This is perfect. I will post pictures when it goes into fabrication!

(Gustavo Fontana) #11

Hola Joaquin, I love your Alias shader, very old school :wink: