fixed improper tesselation order leading to holes in mesh

Author: Tristan

examples/Greens-Theorem_Navier-Stokes.png

@@ -3,7 +3,7 @@
 
 import numpy as np
 
-
+import pylab
 ASCII_FACET = """  facet normal  {face[0]:e}  {face[1]:e}  {face[2]:e}
     outer loop
       vertex    {face[3]:e}  {face[4]:e}  {face[5]:e}
@@ -53,11 +53,16 @@ def writeSTL(facets, file_name, ascii=False):
     f.close()
 
 
+def roll2d(image, shifts):
+    return np.roll(np.roll(image, shifts[0], axis=0), shifts[1], axis=1)
+
+
 def numpy2stl(A, fn, scale=0.1, mask_val=-np.inf, ascii=False,
               calc_normals=False,
               max_width=235.,
               max_depth=140.,
-              max_height=150.):
+              max_height=150.,
+              solid=True):
     """
     Reads a numpy array, and outputs an STL file
 
@@ -91,6 +96,7 @@ def numpy2stl(A, fn, scale=0.1, mask_val=-np.inf, ascii=False,
     A = scale * (A - A.min())
 
     facets = []
+    mask = np.zeros((m, n))
     for i, k in product(range(m - 1), range(n - 1)):
 
         this_pt = np.array([i - m / 2., k - n / 2., A[i, k]])
@@ -111,16 +117,47 @@ def numpy2stl(A, fn, scale=0.1, mask_val=-np.inf, ascii=False,
         if (this_pt[-1] > mask_val and top_right[-1] > mask_val and
                 bottom_left[-1] > mask_val):
 
-            facet = np.concatenate([n1, top_right, this_pt, bottom_left])
+            facet = np.concatenate([n1, top_right, this_pt, bottom_right])
+            mask[i, k] = 1
+            mask[i, k + 1] = 1
+            mask[i + 1, k] = 1
             facets.append(facet)
 
         if (this_pt[-1] > mask_val and bottom_right[-1] > mask_val and
                 bottom_left[-1] > mask_val):
 
             facet = np.concatenate([n2, bottom_right, this_pt, bottom_left])
             facets.append(facet)
+            mask[i, k] = 1
+            mask[i + 1, k + 1] = 1
+            mask[i + 1, k] = 1
     facets = np.array(facets)
 
+    if solid:
+        edge_mask = np.sum([roll2d(mask, (i, k))
+                           for i, k in product([-1, 0, 1], repeat=2)], axis=0)
+        edge_mask[np.where(edge_mask == 9.)] = 0.
+        edge_mask[np.where(edge_mask != 0.)] = 1.
+        edge_mask[0::m - 1,:] = 1.
+        edge_mask[:, 0::n - 1] = 1.
+        X, Y = np.where(edge_mask == 1.)
+        locs = zip(X - m / 2., Y - n / 2.)
+        minval = facets[:, 5::3].min() - 0.1 * facets[:, 5::3].ptp()
+        #[0, 0, 0, 1, 1, z, 1, 1, z, 1, 1, z]
+        bottom = []
+        for i, facet in enumerate(facets):
+            if (facet[3], facet[4]) in locs:
+                facets[i][5] = minval
+            if (facet[6], facet[7]) in locs:
+                facets[i][8] = minval
+            if (facet[9], facet[10]) in locs:
+                facets[i][11] = minval
+            this_bottom = np.concatenate(
+                [facet[:3], facet[6:8], [minval], facet[3:5], [minval], facet[9:11], [minval]])
+            bottom.append(this_bottom)
+
+        facets = np.concatenate([facets, bottom])
+
     xsize = facets[:, 3::3].ptp()
     if xsize > max_width:
         facets = facets * float(max_width) / xsize
@@ -134,3 +171,11 @@ def numpy2stl(A, fn, scale=0.1, mask_val=-np.inf, ascii=False,
         facets = facets * float(max_height) / zsize
 
     writeSTL(facets, fn, ascii=ascii)
+
+
+if __name__ == "__main__":
+    from scipy.ndimage import gaussian_filter
+    A = 256 * pylab.imread("openmdao.png")
+    A =  A[:,:, 0] + 1.*A[:,:, 3] # Compose some elements from RGBA to give depth
+    A = gaussian_filter(A, 2)  # smoothing
+    numpy2stl(A, "OpenMDAO-logo.stl", scale=0.05, mask_val=1.)

examples/Greens-Theorem_Navier-Stokes.stl

@@ -1,6 +1,6 @@
 import os
 import matplotlib as mpl
-mpl.use('Agg')
+mpl.use('Agg', warn=False)
 import matplotlib.pyplot as plt