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[OpenSCAD] Reimplement surface() to match OpenSCAD

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The original implementation of the surface() function used a simple
B-spline representation for the surface, which generated degenerate
surface with several of OpenSCAD's demo input files. This commit
modifies the algorithm to generate a discrete surface identical to the
one generated within OpenSCAD itself. It also adds several units tests
to identify future regressions.

Note that PNG input is not yet supported for the surface() function.
This commit is contained in:
Chris Hennes
2021-03-12 14:51:20 -06:00
committed by wwmayer
parent f55c46cc86
commit 6bf27e0ae1
6 changed files with 186 additions and 31 deletions
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3
src/Mod/OpenSCAD/CMakeLists.txt
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@@ -43,6 +43,9 @@ SET(OpenSCADTestsFiles_SRCS
OpenSCADTest/data/CSG.csg
OpenSCADTest/data/Cube.stl
OpenSCADTest/data/Square.dxf
OpenSCADTest/data/Surface.dat
OpenSCADTest/data/Surface2.dat
OpenSCADTest/data/Surface.png
)
SET(OpenSCADTests_ALL

166
src/Mod/OpenSCAD/OpenSCADFeatures.py
View File

@@ -502,33 +502,139 @@ class CGALFeature:
raise ValueError
def makeSurfaceVolume(filename):
import FreeCAD,Part
f1=open(filename)
coords=[]
miny=1
for line in f1.readlines():
sline=line.strip()
if sline and not sline.startswith('#'):
ycoord=len(coords)
lcoords=[]
for xcoord, num in enumerate(sline.split()):
fnum=float(num)
lcoords.append(FreeCAD.Vector(float(xcoord),float(ycoord),fnum))
miny=min(fnum,miny)
coords.append(lcoords)
s=Part.BSplineSurface()
s.interpolate(coords)
plane=Part.makePlane(len(coords[0])-1,len(coords)-1,FreeCAD.Vector(0,0,miny-1))
l1=Part.makeLine(plane.Vertexes[0].Point,s.value(0,0))
l2=Part.makeLine(plane.Vertexes[1].Point,s.value(1,0))
l3=Part.makeLine(plane.Vertexes[2].Point,s.value(0,1))
l4=Part.makeLine(plane.Vertexes[3].Point,s.value(1,1))
f0=plane.Faces[0]
f0.reverse()
f1=Part.Face(Part.Wire([plane.Edges[0],l1.Edges[0],s.vIso(0).toShape(),l2.Edges[0]]))
f2=Part.Face(Part.Wire([plane.Edges[1],l3.Edges[0],s.uIso(0).toShape(),l1.Edges[0]]))
f3=Part.Face(Part.Wire([plane.Edges[2],l4.Edges[0],s.vIso(1).toShape(),l3.Edges[0]]))
f4=Part.Face(Part.Wire([plane.Edges[3],l2.Edges[0],s.uIso(1).toShape(),l4.Edges[0]]))
f5=s.toShape().Faces[0]
solid=Part.Solid(Part.Shell([f0,f1,f2,f3,f4,f5]))
return solid,(len(coords[0])-1)/2.0,(len(coords)-1)/2.0
import FreeCAD,Part,sys
with open(filename) as f1:
coords = []
min_z = sys.float_info.max
for line in f1.readlines():
sline=line.strip()
if sline and not sline.startswith('#'):
ycoord=len(coords)
lcoords=[]
for xcoord, num in enumerate(sline.split()):
fnum=float(num)
lcoords.append(FreeCAD.Vector(float(xcoord),float(ycoord),fnum))
min_z = min(fnum,min_z)
coords.append(lcoords)
num_rows = len(coords)
num_cols = len(coords[0])
# OpenSCAD does not spline this surface, so neither do we: just create a bunch of faces,
# using four triangles per quadrilateral
faces = []
for row in range(num_rows-1):
for col in range(num_cols-1):
a = coords[row+0][col+0]
b = coords[row+0][col+1]
c = coords[row+1][col+1]
d = coords[row+1][col+0]
centroid = 0.25 * (a + b + c + d)
ab = Part.makeLine(a,b)
bc = Part.makeLine(b,c)
cd = Part.makeLine(c,d)
da = Part.makeLine(d,a)
diag_a = Part.makeLine(a, centroid)
diag_b = Part.makeLine(b, centroid)
diag_c = Part.makeLine(c, centroid)
diag_d = Part.makeLine(d, centroid)
wire1 = Part.Wire([ab,diag_a,diag_b])
wire2 = Part.Wire([bc,diag_b,diag_c])
wire3 = Part.Wire([cd,diag_c,diag_d])
wire4 = Part.Wire([da,diag_d,diag_a])
try:
face = Part.Face(wire1)
faces.append(face)
face = Part.Face(wire2)
faces.append(face)
face = Part.Face(wire3)
faces.append(face)
face = Part.Face(wire4)
faces.append(face)
except Exception:
print ("Failed to create the face from {},{},{},{}".format(coords[row+0][col+0],\
coords[row+0][col+1],coords[row+1][col+1],coords[row+1][col+0]))
last_row = num_rows-1
last_col = num_cols-1
# Create the face to close off the y-min border: OpenSCAD places the lower surface of the shell
# at 1 unit below the lowest coordinate in the surface
lines = []
corner1 = FreeCAD.Vector(coords[0][0].x, coords[0][0].y, min_z-1)
lines.append (Part.makeLine(corner1,coords[0][0]))
for col in range(num_cols-1):
a = coords[0][col]
b = coords[0][col+1]
lines.append (Part.makeLine(a, b))
corner2 = FreeCAD.Vector(coords[0][last_col].x, coords[0][last_col].y, min_z-1)
lines.append (Part.makeLine(corner2,coords[0][last_col]))
lines.append (Part.makeLine(corner1,corner2))
wire = Part.Wire(lines)
face = Part.Face(wire)
faces.append(face)
# Create the face to close off the y-max border
lines = []
corner1 = FreeCAD.Vector(coords[last_row][0].x, coords[last_row][0].y, min_z-1)
lines.append (Part.makeLine(corner1,coords[last_row][0]))
for col in range(num_cols-1):
a = coords[last_row][col]
b = coords[last_row][col+1]
lines.append (Part.makeLine(a, b))
corner2 = FreeCAD.Vector(coords[last_row][last_col].x, coords[last_row][last_col].y, min_z-1)
lines.append (Part.makeLine(corner2,coords[last_row][last_col]))
lines.append (Part.makeLine(corner1,corner2))
wire = Part.Wire(lines)
face = Part.Face(wire)
faces.append(face)
# Create the face to close off the x-min border
lines = []
corner1 = FreeCAD.Vector(coords[0][0].x, coords[0][0].y, min_z-1)
lines.append (Part.makeLine(corner1,coords[0][0]))
for row in range(num_rows-1):
a = coords[row][0]
b = coords[row+1][0]
lines.append (Part.makeLine(a, b))
corner2 = FreeCAD.Vector(coords[last_row][0].x, coords[last_row][0].y, min_z-1)
lines.append (Part.makeLine(corner2,coords[last_row][0]))
lines.append (Part.makeLine(corner1,corner2))
wire = Part.Wire(lines)
face = Part.Face(wire)
faces.append(face)
# Create the face to close off the x-max border
lines = []
corner1 = FreeCAD.Vector(coords[0][last_col].x, coords[0][last_col].y, min_z-1)
lines.append (Part.makeLine(corner1,coords[0][last_col]))
for row in range(num_rows-1):
a = coords[row][last_col]
b = coords[row+1][last_col]
lines.append (Part.makeLine(a, b))
corner2 = FreeCAD.Vector(coords[last_row][last_col].x, coords[last_row][last_col].y, min_z-1)
lines.append (Part.makeLine(corner2,coords[last_row][last_col]))
lines.append (Part.makeLine(corner1,corner2))
wire = Part.Wire(lines)
face = Part.Face(wire)
faces.append(face)
# Create a bottom surface to close off the shell
a = FreeCAD.Vector(coords[0][0].x, coords[0][0].y, min_z-1)
b = FreeCAD.Vector(coords[0][last_col].x, coords[0][last_col].y, min_z-1)
c = FreeCAD.Vector(coords[last_row][last_col].x, coords[last_row][last_col].y, min_z-1)
d = FreeCAD.Vector(coords[last_row][0].x, coords[last_row][0].y, min_z-1)
ab = Part.makeLine(a,b)
bc = Part.makeLine(b,c)
cd = Part.makeLine(c,d)
da = Part.makeLine(d,a)
wire = Part.Wire([ab,bc,cd,da])
face = Part.Face(wire)
faces.append(face)
s = Part.Shell(faces)
solid = Part.Solid(s)
return solid,last_col,last_row

33
src/Mod/OpenSCAD/OpenSCADTest/app/test_importCSG.py
View File

@@ -313,7 +313,38 @@ polyhedron(
FreeCAD.closeDocument(doc.Name)
def test_import_surface(self):
pass
testfile = join(self.test_dir, "Surface.dat").replace('\\','/')
doc = self.utility_create_scad(f"surface(file = \"{testfile}\", center = true, convexity = 5);", "surface_simple_dat")
object = doc.ActiveObject
self.assertTrue (object is not None)
self.assertAlmostEqual (object.Shape.Volume, 275.000000, 6)
self.assertAlmostEqual (object.Shape.BoundBox.XMin, -4.5, 6)
self.assertAlmostEqual (object.Shape.BoundBox.XMax, 4.5, 6)
self.assertAlmostEqual (object.Shape.BoundBox.YMin, -4.5, 6)
self.assertAlmostEqual (object.Shape.BoundBox.YMax, 4.5, 6)
FreeCAD.closeDocument(doc.Name)
testfile = join(self.test_dir, "Surface.dat").replace('\\','/')
doc = self.utility_create_scad(f"surface(file = \"{testfile}\", convexity = 5);", "surface_uncentered_dat")
object = doc.ActiveObject
self.assertTrue (object is not None)
self.assertAlmostEqual (object.Shape.Volume, 275.000000, 6)
self.assertAlmostEqual (object.Shape.BoundBox.XMin, 0, 6)
self.assertAlmostEqual (object.Shape.BoundBox.XMax, 9, 6)
self.assertAlmostEqual (object.Shape.BoundBox.YMin, 0, 6)
self.assertAlmostEqual (object.Shape.BoundBox.YMax, 9, 6)
FreeCAD.closeDocument(doc.Name)
testfile = join(self.test_dir, "Surface2.dat").replace('\\','/')
doc = self.utility_create_scad(f"surface(file = \"{testfile}\", center = true, convexity = 5);", "surface_rectangular_dat")
object = doc.ActiveObject
self.assertTrue (object is not None)
self.assertAlmostEqual (object.Shape.Volume, 24.5500000, 6)
self.assertAlmostEqual (object.Shape.BoundBox.XMin, -2, 6)
self.assertAlmostEqual (object.Shape.BoundBox.XMax, 2, 6)
self.assertAlmostEqual (object.Shape.BoundBox.YMin, -1.5, 6)
self.assertAlmostEqual (object.Shape.BoundBox.YMax, 1.5, 6)
FreeCAD.closeDocument(doc.Name)
def test_import_projection(self):
pass

10
src/Mod/OpenSCAD/OpenSCADTest/data/Surface.dat Normal file
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@@ -0,0 +1,10 @@
10 9 8 7 6 5 5 5 5 5
9 8 7 6 6 4 3 2 1 0
8 7 6 6 4 3 2 1 0 0
7 6 6 4 3 2 1 0 0 0
6 6 4 3 2 1 1 0 0 0
6 6 3 2 1 1 1 0 0 0
6 6 2 1 1 1 1 0 0 0
6 6 1 0 0 0 0 0 0 0
3 1 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0 0

BIN
src/Mod/OpenSCAD/OpenSCADTest/data/Surface.png Normal file
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5
src/Mod/OpenSCAD/OpenSCADTest/data/Surface2.dat Normal file
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@@ -0,0 +1,5 @@
# Example comment
1.0 1.1 1.3 1.7 2.5
1.1 1.3 1.7 2.5 2.7
1.3 1.7 2.5 2.7 2.9
1.7 2.5 2.7 2.9 3.0