Closed solid without closed curves; problem with hydrostatics function

Dear all,

I have a model on which I would like to use the hydrostatics function. Rhino is able to make a solid out of curves, but the hydrostatics function won’t work. Making an intersection shows that the curves are not closing (although the solid is) and the opening is 1.78 mm. Any advice on how to solve this?

Thanks in advance, Hanna

intersect1 M9359_201119.3dm (915.8 KB)

At which height is the intersection plane?

Somewhere in between 1600 and 1950 it would occur.

*somewhere = everywhere

Hi Hanna -
You have set your document tolerances to 2 units.

I’m afraid that will give you nothing but trouble. Generally keep the units tolerance in the .01 > .000001 range to keep Rhino happiest.

Also, the surfaces that are selected in this image appear to be completely flat so they should be able to be modeled as very simple surfaces instead of these overly dense patches.


The selected surfaces are problematic. The red curve has a lot of points… Another problem is around the two ends. I deleted the two the two ends and capped the polysurface.

I rebuilt some more surfaces since they were a mess. Not 100 % clean yet.

M9359_201119.3dm (633.8 KB)

Many thanks Martin! The hydrostatics function now does its work. Which functions did you use for rebuilding the surface?

Thanks for the reply Wim. The model was actually build up with 0.01 mm tolerances but I tried to make it work with the 2 mm tolerance. Rebuilding the surface like Martin did does work.

I’ve used the Cap command for the two ends and Sweep 2 for the side, together with your red curves.

Between z=1850 and z=2000 still problems occur. When I make an intersection, no intersection is made ‘underneath’ the ship. Any solution for this?


I suggest to use _PlanarSrf

I’ve looked at the model again. My rebuilt surfaces are actually not very nice. There are more surfaces with edges that have way too many control points. That leads to problems with sections