In [1]:

    

import numpy as np

%matplotlib inline
import matplotlib as mpl
import matplotlib.pyplot as plt

mpl.rcParams['figure.figsize'] = (16, 9)

import sys
import imp
import os

import polymesh.mesh as mesh
import polymesh.hydrostatic as hydrostatic


    

In [2]:

    

# Import the test geoemtry, which is a full size version of the ship KCS
shipMesh = mesh.importObj('BrAa_40m_hull_side_offset.obj')

scale_to_small_vessel   = True

L_small                 = 27
B_small                 = 8.5
L_orig                  = 40
B_orig                  = 10



if scale_to_small_vessel:
    L_scale_ratio       = L_small/L_orig
    B_scale_ratio       = B_small/B_orig
    shipMesh.scale(L_scale_ratio, B_scale_ratio, B_scale_ratio)


# The keel is located at z=0 in the geometry file. Translate it downwards to right depth
T = 1.65
if scale_to_small_vessel:
    T = 1.11
shipMesh.translate(0, 0, -T)


    

In [3]:

    

rho = 1025

wetMesh = hydrostatic.extractWetSurface(shipMesh)
wetMesh.exportObj('wetMesh.obj')
wetMesh.calculateEdgeConnectivity()

Volume         = hydrostatic.calculateVolume(wetMesh)
Surface        = hydrostatic.calculateSurface(wetMesh)
volumeCentroid = hydrostatic.calculateVolumeCentroid(wetMesh)
Dimensions     = hydrostatic.calculateDimensions(wetMesh) 
Mass = Volume*rho

print('Volume:', np.round(Volume, decimals=3), 'm^3')
print('Surface:', np.round(Surface, decimals=3), 'm^2')
print('Volume centroid:', np.round(volumeCentroid[0], decimals=4), np.round(volumeCentroid[1], decimals=4), np.round(volumeCentroid[2], decimals=4))
print('Dimensions:', Dimensions)
print('Mass:', Mass/1e3, 'tonnes')


    

    




Volume: 36.683 m^3
Surface: 83.257 m^2
Volume centroid: 11.0804 3.1013 -0.4456
Dimensions: [26.92736184  2.18867951  0.2521341 ]
Mass: 37.599853412766436 tonnes

In [4]:

    

plt.scatter(wetMesh.verts[wetMesh.face_verts][:,0], wetMesh.verts[wetMesh.face_verts][:,2])
plt.axis('equal')
plt.figure()
plt.scatter(wetMesh.verts[wetMesh.face_verts][:,1], wetMesh.verts[wetMesh.face_verts][:,2])
plt.axis('equal')


    

    
Out[4]:





(1.8888696372451526,
 4.316130362754846,
 -1.1806507179415011,
 0.07067536794150114)






    













    

In [4]:

    

shipMesh.translate(0, 0, T) 
wetMesh.translate(0, 0, T)


    

In [5]:

    

extrude_vert        = True
extrude_vert_len    = 5.0
add_center_point    = True

n_planes    = 101
norm_axis   = 0
sort_axis   = 1

mesh_       = wetMesh

plt.scatter(mesh_.verts[mesh_.face_verts][:,0], mesh_.verts[mesh_.face_verts][:,1])
plt.axis('equal')
ax_min      = np.amin(mesh_.verts[mesh_.face_verts][:,0])
ax_max      = np.amax(mesh_.verts[mesh_.face_verts][:,0])
ax_len      = ax_max-ax_min
d_long      = (ax_len)/(n_planes-1)
pos_long    = np.zeros(n_planes)
plane_points= []


for i in range(n_planes):
    pos_long[i] = ax_min + i*d_long
    plane       = hydrostatic.extractPlane(wetMesh, norm_axis, pos_long[i])
    points      = plane[0]
    points      = points[points[:,sort_axis].argsort()]
    if extrude_vert:
        inner_point     = points[0,:]
        outer_point     = points[-1,:]
        new_inner_point = inner_point + extrude_vert_len*np.array((0,0,1.0))
        new_outer_point = outer_point + extrude_vert_len*np.array((0,0,1.0))
        points          = np.vstack((new_inner_point, points))
        points          = np.vstack((points, new_outer_point))
        
    if add_center_point:
        inner_point_z = points[0,2]+.01
        new_inner_point = np.array((pos_long[i], 0, inner_point_z))
        points      = np.vstack((new_inner_point, points))
    plane_points.append(points)


    

In [6]:

    

plt.scatter(mesh_.verts[mesh_.face_verts][:,0], mesh_.verts[mesh_.face_verts][:,2])
plt.axis('equal')
plt.figure()
plt.scatter(mesh_.verts[mesh_.face_verts][:,1], mesh_.verts[mesh_.face_verts][:,2])
plt.axis('equal')


    

    
Out[6]:





(1.8888696372451526,
 4.316130362754846,
 -0.07065071794150102,
 1.1806753679415012)






    













    

In [7]:

    

plane_no = 67
plt.figure()
plt.plot(plane_points[plane_no][:,1],plane_points[plane_no][:,2])
plt.tight_layout()


print(np.min(plane_points[plane_no][:,2]))


    

    




0.0005240976780471585






    

In [10]:

    

save_location = '/home/johnmartingodo/Dropbox/Flying Foil/Prosjekter/Utviklingskontrakt Trøndelag/Gjennomføring/Hovedprosjekt/Regularitet og komfort/Skroggeometri/Original_40m/'
vessel_name = 'BrAa_40m_hull'

if scale_to_small_vessel:
    save_location = '/home/johnmartingodo/Dropbox/Flying Foil/Prosjekter/Utviklingskontrakt Trøndelag/Gjennomføring/Hovedprosjekt/Regularitet og komfort/Skroggeometri/Scaled_30m/'
    vessel_name = 'BrAa_30m_hull_scaled_from40'


f           = open(save_location+vessel_name+'.mgf', 'w')
f.write(vessel_name+'\n')
for i in range(3):
    f.write('\n')
f.write(str(ax_len)+'\n')

for i in range(n_planes-1):
    plane_index     = n_planes-2-i
    shpx_index      = plane_index+1
    
    f.write(str(shpx_index)+'\n')
    f.write(str(pos_long[plane_index]-.5*ax_len)+'\n')
    n_points_plane = len(plane_points[plane_index])
    f.write(str(n_points_plane)+'\n')
    for j in range(n_points_plane):
        point_index     = n_points_plane-1-j
        f.write('{:.8f}    {:.8f}\n'.format(plane_points[plane_index][point_index,1], plane_points[plane_index][point_index,2]))
    


f.close()


    

In [ ]: