Marine Hydrostatics. Someone help me!

[huochu49]

Hi everybody. I closed brep. How to turn off the blue polysurface? please

[huochu49]

hope pls!

[wim (Wim Dekeyser)]

Hi -

@huochu49

How to turn off the blue polysurface?

You are asking people to guess what they are seeing in an image…
Hide the geometry in Rhino, perhaps?
-wim

[Erik_Beeren]

@huochu49
You can turn of the layer in Rhino.

[huochu49]

Ship shapes overlap. do you see any other way?

[huochu49]

I don’t want the ship’s shape to overlap

[Joseph_Oster]

I think it’s fair to note that the hydrostatics model you are using is from me:
http://www.islandcad.com/grasshopper/hydrostatics/

The displacement of “1.9817e+10” looks suspect? Mix-up in units, perhaps?

[huochu49]

Thank you very much. Thank you for your file

[Joseph_Oster]

In addition to mixed up units, your boat hull is not a “Closed Brep” and the CloseBrep cluster I provided fails to do the job properly.

To use this code, your boat must be positioned floating at rest on its lines at the origin (Z = 0 is water level). Then follow the ‘Z-offset’ Solver instructions

‘Z-offset’ Solver - Instructions

1. Set “Stop / Start” (below) to ‘Solver Off’
2. Click to enable ‘Rec’ (“record ‘Target’”) above.
3. Zero ‘Pitch’, ‘Roll’ and ‘Z-offset’ to initialize ‘Target’ value.
4. Make sure ‘Target’ is valid, then click to DISABLE ‘Rec’.
5. Adjust ‘Roll’ (5 to 35) and/or ‘Pitch’ (3 to 10) degrees.
6. Set Z-Offset “Source” to “Solver” (IMPORTANT!)
7. Set “Stop / Start” to ‘Solver On’

‘Target’ value is the boat’s displacement in cubic feet of seawater, which is derived for you based on the hull’s at rest position. Best that you experiment first with one of the sample hulls provided.

@huochu49

I closed brep.

[huochu49]

@Joseph_Oster

your boat must be positioned floating at rest on its lines at the origin (Z = 0 is water level).

Thank you so much! but i am newbie.hic

[huochu49]

@Joseph_Oster

your boat must be positioned floating at rest on its lines at the origin (Z = 0 is water level).

your boat must be positioned floating at rest on its lines at the origin (Z = 0 is water level) .
Can you guide me where the line is?

[huochu49]

Can you guide to set z=0 with video? thank you

[Joseph_Oster]

@huochu49

but i am newbie.hic

Yeah, and apparently English isn’t your native language?

As to positioning the boat, alternative hulls are supplied in the GH file that show what is expected.

As to dealing with unit differences, that will require a methodical review - unless you convert your units to feet.

[huochu49]

You are very enthusiastic to guide! HIC

[Joseph_Oster]

I changed Rhino units from millimeters to feet and answered this question “Yes”:

I didn’t try to figure out why your hull is not a closed brep. Instead, I baked your hull and deleted many surfaces that were details of the interior, then manually drew surfaces to close the deck opening. I added a new layer to the Rhino file for this, “plug”, with sub-layers for “deck” and “hull”.

I left pitch at zero degrees but set the ‘Z-offset’ slider to -1.5 (feet!), which computes a displacement of 11,636 pounds for this hull that is 40 feet long. Is that close to what you have in mind?

Hydrostatics_2023_Jul24a.gh (206.5 KB)
GHS_2023Jul24a.3dm (2.8 MB)

[Joseph_Oster]

This uses a newer copy of that old code, with the ‘Z-Offset Solver’ showing bow pitch down two degrees:

Hydrostatics_2023_Jul24b.gh (207.8 KB)

This old code really needs to be updated…

Displacement equilibrium with bow down ten degrees:

[huochu49]

Thank you so much!!.
I will try

[huochu49]

Have a nice day and good luck