Ellipse¶

Part.Sphere() produces a face and Part.makeSphere() produces a solid, but there is not yet a Part.makeEllipsoid() to make a solid.

An ellipsoid can be produced by revolving an ellipse. If the ellipse is not filled in (has no faces) then the revolution will be hollow.

The following shows different ways to use an ellipse to make a solid ellipsoid with the general shape of a rugby ball. (It could be made to look like a flying saucer but that will be left to the reader.)

Part.Ellipse().toShape() makes a shape that is an edge with no faces. The ellipsoid made by revolving this has faces but is not solid (a hollow ellipsoid).

To start, make an ellipse, on the XY-plane through the origin, with radii, 6.0 and 2.0.

e = Part.Ellipse(o, 6.0, 2.0)
print(len(e.toShape().Faces))
#Part.show(e.toShape())

Create a half ellipse on the XY-plane with ends on the X-axis and revolve it a full turn around the X-axis using method revolve()

eh = e.toShape(0, e.LastParameter/2)
#Part.show(eh)
print( eh.ShapeType )  #Edge
print( len(eh.Solids)) # 0
#TEST ON Z AXIS
ecS = eh.revolve(o, x, 360)
#Part.show(ecS )
print( ecS.ShapeType )  #Face
print( len(ecS.Solids)) # 0
print( ecS.isClosed() )  #False #Looks like a BUG.
print( ecS.isValid()  ) #True

e1 = Part.makeSolid(Part.makeShell([ecS]))
#Part.show(e1 )
print( e1.ShapeType )  #Solid
print( len(e1.Solids)) # 1
print( e1.isClosed() ) #True
print( e1.isValid()  ) #True

#( still trying Part.makeRevolution arg need to be GeomCurve)
#ecS = Part.makeRevolution(e, 0, e.LastParameter/2, 360, o, x)
#ecS = Part.makeRevolution(eh, eh.LastParameter, 0, 360, o, x)
#Part.OCCDomainError: creation of revolved shape failed    BUG ???

Edge
0
Face
0
False
True
Solid
1
True
True

1/ revolve full ellipse a half turn around the x axis

#ed = Part.makeRevolution(e.toShape(), 0, e.LastParameter, 180, o, x)

ed = e.toShape().revolve(o, y, 180) #saucer THIS SHOULD USE x BUT THAT FAILS
#Part.show(ed)
print(ed.ShapeType)   # Face  (hollow ellipsoid)
print(len(ed.Solids)) # 0
print(len(ed.Faces))  # 1
print( ed.isClosed() )  #False #Looks like a BUG.
print( ed.isValid()  ) #True

#TRY THIS IN GUI
#ed1 = e.toShape().revolve(o, x, 180) # should be rugby ball but
#Part.show(ed1)            # does not show
#print( ed1.ShapeType )  #Face
#print( len(ed1.Solids)) # 0
#print( ed1.isClosed() )  #False #Looks like a BUG.
#print( ed1.isValid()  ) #True
#ed1.PrincipalProperties

Face
0
1
False
True

I THINK THIS IS THE SAME AS FIRST NOW An algorithmically better way to make an ellipsoid, according to the revolve documentation, is to cut the ellipse so there are vertices. LastParameter is 2 pi radians so this cuts the sweep to the half circle from 0 to pi:

e = Part.Ellipse(o, 6.0, 2.0)
h = e.toShape(0, e.LastParameter/2)
#Part.show(h)
hd = h.revolve(o, x, 360) #rugby ball, hollow
ed2 = Part.makeSolid(Part.makeShell([hd]))
#Part.show(ed2)

print(h.ShapeType)     #Edge
print(hd.ShapeType)    #Face
print(ed2.ShapeType)   #Solid
print(len(ed2.Solids)) #1
print(hd.isClosed())   #False   ???
print(hd.isValid())    #True

print(len(ed2.Faces))  #1
#DO TESTEQUAL

Edge
Face
Solid
1
False
True
1

3/ a different 1/2 ellipse revolved around long axis, mirror and join

NOT YET WORKING

e3 = e.toShape(e.LastParameter/4, 3*e.LastParameter/4)
#Part.show(e3)

#THESE ROTATION WORKS FINE DESPITE NOT THROUGH VERTEXES
#hd = e3.revolve(o, x, 360) #half rugby hollow, double cover Also works
hd = e3.revolve(o, x, 180) #half rugby hollow, singe cover
#Part.show(hd)
print(hd.ShapeType)   #Face
print(len(hd.Solids)) #0
print(hd.isClosed())  #False   ???
print(hd.isValid())   #True

hdm = hd.mirror(o, x)
#Part.show(hdm)
print(hdm.ShapeType)   #Face
print(len(hdm.Solids)) #0
print(hdm.isClosed())  #False   ???
print(hdm.isValid())   #True)

#check = Part.makeShell([hdm])
#Part.show(check)
#sh3 = Part.makeShell([hd, hdm]) #SUPPOSED TO MAKE SHELL FROM LIST OF FACES BUT LOSES hdm

TRY THIS IN GUI

#sh3 = Part.makeShell([hd.Faces + hdm.Faces]) #Part.show(sh3) # no show print(sh3.ShapeType) #Face print(len(sh3.Solids)) #0 print(sh3.isClosed()) #False ??? print(sh3.isValid()) #True

#ed3 = Part.makeSolid(sh3) #Part.show(ed3) # ONLY HALF

#filled= Part.makeFilledFace(hd.toShape().Edges)

#rugby = hd.fuse(hdm) # No. Fuse wants solids (warning only in gui) #Part.show(rugby)

Face
0
False
True
Face
0
False
True

4/ 1/4 ellipse revolved to give 1/2 ellipsoid, mirror and join

NOT YET

e = Part.Ellipse(o, 6.0, 2.0).toShape()
#Part.show(e)
ed = e.revolve(o, y, 180) #saucer
#Part.show(ed)
#ed1 = Part.makeShell(ed) #Error creating objec
#ed2 = Part.makeSolid(ed) # Creation of solid failed: No shells
#Part.show(ed2)
print( len(ed.Solids) )

construct 2nd half rather than mirror

NOT YET

e = Part.Ellipse(o, 6.0, 2.0).toShape()
#Part.show(e)
ed = e.revolve(o, y, 180) #saucer
#ed = e.revolve(o, x, 180) # why not rugby ball
#Part.show(ed)

e2 = Part.Ellipse(o, 6.0, 2.0).toShape()
e2.rotate(o,  z,  90)
#Part.show(e2)
ed2 = e2.revolve(o, y, 180) # why not
ed2 = e2.revolve(o, x, 180) # why saucer
#Part.show(ed2)
testNotEqual(e, e2)
e.rotate(o,  x,  90)
e2.translate(x)
e2.rotate(x,  x,  90)
e2.rotate(x,  z, -90)
e2.translate(-x)
#testEqual(e, e2)

wi = Part.Wire(e)
print(wi.isClosed())  #True

d = Part.Face(wi)
dd = d.extrude(Vector(20,0,0))
#Part.show(dd)

#b = Part.makeCylinder(8, 20, o, x, 90)
#b = b.cut(dd)

True

This would not need to be rotated, but s2 does not work the way I think # e2 = Part.Ellipse(Vector(0.0, 0.0, 6),Vector(0.0, 2, 8), Vector(0.0, 0.0, 8)).toShape() #Part.show(e2)

An ellipsoid with equal radii is a circle a sphere made this way can be compared with a sphere made with makeSphere().

eC = Part.Ellipse(o, 5.0, 5.0)
edC = Part.makeSolid(Part.makeShell([
          eC.toShape(0, eC.LastParameter/2).revolve(o, x, 360)  ]))

# Part.show(edC)
testEqual( edC,Part. makeSphere(5) )

Try above using makeRevolution.

eC = Part.Ellipse(o, 5.0, 5.0)
ech = eC.toShape(0, eC.LastParameter/2)
#ecS = Part.makeRevolution(ech.Curve)
#ecS = Part.makeRevolution(ech)
#ecS = Part.makeRevolution(ech, ech.FirstParameter, ech.LastParameter, 360, o, x, Part.Solid)

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