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74 lines
2.5 KiB
Python
74 lines
2.5 KiB
Python
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from netgen.meshing import *
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def ReadGmsh (filename):
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f = open(filename, 'r')
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mesh = Mesh(dim=3)
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pointmap = { }
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facedescriptormap = { }
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while True:
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line = f.readline()
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if line == "": break
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if line.split()[0]=="$Nodes":
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num = int(f.readline().split()[0])
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print ("reading",num,"nodes")
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for i in range(num):
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line = f.readline()
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nodenum,x,y,z = line.split()[0:4]
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pnum = mesh.Add (MeshPoint(Pnt(float(x),float(y),float(z))))
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pointmap[int(nodenum)] = pnum
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if line.split()[0]=="$Elements":
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num = int(f.readline().split()[0])
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print ("reading",num,"elements")
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for i in range(num):
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line = f.readline().split()
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elmnum = int(line[0])
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elmtype = int(line[1])
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numtags = int(line[2])
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tag1 = int(line[3])
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if elmtype == 2: # 3-node trig
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num_nodes = 3
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elif elmtype == 3: # 4-node quad
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num_nodes = 4
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elif elmtype == 4: # 4-node tet
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num_nodes = 4
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else:
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print ("element type", elmtype, "not implemented")
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nodenums = line[3+numtags:3+numtags+num_nodes]
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nodenums2 = [ pointmap[int(nn)] for nn in nodenums ]
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if elmtype in [2,3]: # 2d elements
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# generate facedescriptor for boundary conditon number,
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# first tag is used as bc-number
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# element index maps into facedescriptor array
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if tag1 in facedescriptormap.keys():
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fdindex = facedescriptormap[tag1]
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else:
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fd = FaceDescriptor(bc=tag1)
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fdindex = mesh.Add(fd)
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facedescriptormap[tag1] = fdindex
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mesh.Add (Element2D(fdindex, nodenums2))
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if elmtype == 4: # 4-node tet
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nodenums2 = [ pointmap[int(nn)] for nn in nodenums ]
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mesh.Add (Element3D(tag1, [nodenums2[0],nodenums2[1],nodenums2[3],nodenums2[2]]))
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print (nodenums2)
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# print (mesh)
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# print (pointmap)
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return mesh
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# ReadGMSH ("test.gmsh")
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