GeoSteiner output parser and import to blender

fst2json.py

"""
FST (Full Steiner tree) generator Version 3 parser
Documentation: http://geosteiner.com/geosteiner-5.1-manual.pdf (page 186)

How to use: "./rand_points 10 | ./efst | ./bb -f | python3 fst2json.py"

To note, an alternate method is to grep for the " % @C	XXX	YYY" output from `bb`,
to get the Steiner points. (page 158 of the manual)
"""

import json

try:
    input = raw_input
except NameError:
    pass

def line():
	return input().replace('\t', ' ').strip()


METRICS = ['Rectilinear', 'Euclidean', 'Graph']
FST_STATUS = ["never needed", "maybe needed", "always needed"]

data = {
	"version": line(),
	"instance": line(),
	"metric": METRICS[int(line())],
	"number_of_terminals": int(line()),
	"length_minimum_steiner_tree": float(line().split()[0]),
	"scaling_factor": line(),
	"decimal_integrality": float(line().split()[0]),
	"machine": line(),
	"cpu_time": int(line()),
	"number_of_FSTs": int(line()),
	"terminals_coords": [],
	"terminal_is_not_a_steiner_point": [],
	"fsts": [],
}

for _ in range(data["number_of_terminals"]):
	x, y = line().split()[:2]
	data["terminals_coords"].append([
		float(x),
		float(y),
	])

data["terminal_is_not_a_steiner_point"] = [int(x) for x in line().split()]

for _ in range(data["number_of_FSTs"]):
	fst_data = {
		"number_of_terminals": int(line()),
		"terminals_indices": [int(x) for x in line().split()],
		"length": float(line().split()[0]),
		"n_steiner": int(line()),
		"steiner_coords": [],
	}

	for _ in range(fst_data["n_steiner"]):
		x, y = line().split()[:2]
		fst_data["steiner_coords"].append([
			float(x),
			float(y),
		])
	
	fst_data["n_edges"] = int(line())
	fst_data["edges"] = []
	for _ in range(fst_data["n_edges"]):
		origin, dest = line().split()
		fst_data["edges"].append([int(origin), int(dest)])

	fst_data["status"] = FST_STATUS[int(line())]
	fst_data["n_incompatible_fsts"] = int(line())
	if fst_data["n_incompatible_fsts"]:
		fst_data["incompatible_fsts"] = line().split()

	data["fsts"].append(fst_data)

print(json.dumps(data, indent=2))

import-in-blender.py

# based on http://wiki.theprovingground.org/blender-py-mathmesh
# and https://askubuntu.com/questions/325485/how-to-make-a-mesh-by-using-python-script-on-blender#325515

import bpy
import math
from pprint import pprint as pp

import json


# clear mesh and object
for item in bpy.context.scene.objects:
    if item.type == 'MESH':
        bpy.context.scene.objects.unlink(item)
for item in bpy.data.objects:
    if item.type == 'MESH':
        bpy.data.objects.remove(item)
for item in bpy.data.meshes:
    bpy.data.meshes.remove(item)
for item in bpy.data.materials:
    bpy.data.materials.remove(item)


data_path = "/path/to/your/fst2json/output"
data = json.load(open(data_path))

pp(data)
 
# mesh arrays
verts = []
faces = []
edges = []

# get real index of the point (page 181 of the manual)
def conv(fst, x):
    # terminal
    if x > 0: return fst["terminals_indices"][x - 1] - 1
    # steiner point
    if x < 0: return len(verts) - len(fst["steiner_coords"]) - x - 1


for x, y in data["terminals_coords"]:
    verts.append((x, y, 0))


for fst in data["fsts"]:
    for x, y in fst["steiner_coords"]:
        verts.append((x, y, 0))

    print('len verts', len(verts))
    for org, dst in fst["edges"]:
        print('edge', org, dst)
        org, dst = conv(fst, org), conv(fst, dst)
        print('  ->', org, dst)
        edges.append((org, dst))
   
print(verts)
print(edges)

# sanity check to avoid crashes
for org, dst in edges:
    if not (len(verts) > org >= 0 and len(verts) > dst >= 0):
        print("verts=", len(verts), "org=", org, "dst=", dst)
        ooops
        

#create mesh and object
mesh = bpy.data.meshes.new("steiner-tree")
object = bpy.data.objects.new("steiner-tree",mesh)
 
#set mesh location
object.location = bpy.context.scene.cursor_location
bpy.context.scene.objects.link(object)
 
#create mesh from python data
mesh.from_pydata(verts, edges,faces)