get area of section voxel sits in

voxelise.py

 import sys
+import matplotlib.pyplot as plt
 import numpy as np
 import time
 import pandas as pd
@@ -11,6 +12,19 @@ import pandas as pd
 import json
 import utils as tu
 from os.path import exists
+import reebgraph
+import pymeshfix as pf
+import trimesh as tm
+from shapely.geometry import Point
+
+
+def to_trimesh(mesh):
+    """
+    Converts a mesh into a trimesh format
+    """
+    mesh_fix = pf.MeshFix(mesh)
+    trimesh_mesh = tm.base.Trimesh(vertices=mesh_fix.v, faces=mesh_fix.f)
+    return trimesh_mesh
 
 
 def voxelised_csv(mesh_file_name,
@@ -116,14 +130,56 @@ def contour2dict(c):
     return {'pos':c.pos, 'time':c.time}
 
 
+def vox_section_area(voxels, mesh_file_name):
+    mesh = pv.read(mesh_file_name)
+    tu.transform_to_bed_centre(mesh, [110, 110, 0])
+    tu.transform_to_z0(mesh)
+    tm_mesh = to_trimesh(mesh)
+    SecArea = np.zeros(len(voxels))
+
+    z = 0
+    i = 0
+    while 0 in SecArea:
+        i = np.where(SecArea==0)[0][0]
+        c = voxels.iloc[i,1:4].to_numpy()
+        print(c)
+
+        # if new slice required
+        if c[2] != z:
+            sl = tm_mesh.section(plane_origin=c, plane_normal=[0,0,1])
+            if sl is None:
+                SecArea[i] = 1e7
+                continue
+            sl2d,_ =sl.to_planar()
+            z = c[2]
+
+        for e in sl2d.split():
+            e.apply_translation(-sl2d.centroid)
+            e.apply_translation(sl.centroid[0:2])
+            poly = e.polygons_full[0]
+
+            if poly.contains(Point(c[:2])):
+                SecArea[i] = poly.area
+     
+        if SecArea[i] == 0:
+            # TODO HACK so it uses neighbour's SecArea
+            SecArea[i] = 1e7
+
+        if z>3:
+            break
+
+
 if __name__ == '__main__':
     obj = 'models/M9'
     #check_data(obj + '.stl', obj + '_raw.csv', from_inches=True)
     #out = voxelised_csv(obj + '.stl', obj + '_raw.csv', voxels=obj+'_vox_centers.csv', from_inches=True)
     #out.to_csv(obj + '_voxels.csv')
-    visualise_voxels(obj + '_voxels.csv')
+    #visualise_voxels(obj + '_voxels.csv')
+
+    voxels = pd.read_csv(obj + '_voxels.csv')
+    vox_section_area(voxels, obj + '.stl')
 
     #contours = gc.decode_gcode(obj + '.gcode')
     #outfile = open(obj + 'contours.json','w')
     #json.dump([contour2dict(c) for c in contours], outfile)
-    outfile.close()
+    #outfile.close()