Been asked before, but it seems that I don’t get it working …
I have a list of 5 Autodesk.Revit.DB.PlanarFace which I want to check if they are parallel to eachother.
So it seems to me I have to convert the term PlanarFace to something I can use in Dynamo?
If so: ToProtoType / ToRevitType aren’t working …
If it is just to check if they are parallel, would be enough by comparing their FaceNormal vectors? Converting to Dynamo surface geometry is quite an expensive task.
Okay @alvpickmans , I for sure don’t want to make the script “heavy” if not needed!
So sticking with python… that rises the next question: how do I compare the FaceNormal?
PlanarFace.Normal … PlanarFace object has no attribute Normal …?
You need to use PlanarFace.FaceNormal property, which gives you the XYZ normal vector for that face.
As far as I remember, two vectors are parallel if their dot product equals to 1. Revit XYZ vectors have the DotProduct method which you can use to compare them.
@alvpickmans, thanks. FaceNormal: check.
DotProduct: doens’t seem to be recognized?
import clr
clr.AddReference('ProtoGeometry')
from Autodesk.DesignScript.Geometry import *
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import *
clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)
clr.ImportExtensions(Revit.Elements)
clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
# INPUT ELEMENTS FROM REVIT
a = IN[0]
b = []
for n in a:
b.append(n.FaceNormal)
c = DotProduct(b)
OUT = b,c
So: IN is a list of planarfaces. …
Can you share your code and test file?
without trying this myself, I assume DotProduct method will need to be called from a XYZ vector instance and compared to another vector in order to perform the calculation.
v1 = #vector 1
v2 = #vector 2
dotProduct = v1.DotProduct(v2)
Depending on your final goal, the code will be implemented on different ways…could you provide a Revit test file and waht you want to achieve? 
Alternatively you can go old fashioned and calculate the dotproduct using standard mathematical constructs:
(Thanks to: https://stackoverflow.com/questions/35208160/dot-product-in-python-without-numpy)
def dot(v1, v2):
return sum(x*y for x,y in zip(v1,v2))
p = dot([1,2,3], [4,5,6])@Jonathan.Olesen, can’t use * with vectors 
@alvpickmans, yes I agree that is how it is used. So I guess since I have a list with vectors I have to cross check each value with that list.
a = IN[0]
b = a[0].DotProduct(a[1])
OUT = b
but this is only for one
a = IN[0]
b = combinations(a)
OUT = b
???
Hi @3Pinter I don’t see why my method cannot be used with vectors?
V1 = IN[0]
V2 = IN[1]
def dot(v1,v2):
return sum(x*y for x,y in zip(v1,v2))
p = dot([V1.X,V1.Y,V1.Z],[V2.X,V2.Y,V2.Z])
OUT = p
Because I have to check whether the vectors are parralel. So the list I have (5 planes) have 2 sets of parallels. Those I want as a list.
So I believe I would have to:
a = IN[0]
def dot(v1, v2):
return sum(x*y for x,y in zip(v1,v2))
p = dot(a,a)
OUT = p
where a = a list:
[0] (-1, 0, 0)
[1] (0, 0, 1)
[2] (1,0,0)
[3] (0.0,-1)
[4] (0,-1,0)
Makes sense? Or am I making no sense at all?
I mean a list a 5 means 15 unique combinations.
(00,01,02,03,04,11,12,13,14,22,23,24,33,34,44)
a = IN[0]
b = []
stepcounter = 0
for step1 in a:
for i in range(len(a)):
b.append(step1.DotProduct(a[i]))
OUT = b
This gives me ALL the possible combinations (including doubles) … now I have to reduce the loop…
ok. 15 unique combintions done. But shouldn’t it be:
List:
[0]
—[0] 0
—[1] -1
—[2] 0
—[3] 0
[1]
etcetc
So I can get a list which vector is parallel to which other vector in that list.
Like so:
The first “1” is the list compared to itself, this can be avoided using “x+1” instead of “x” in the second loop.
thanks, will look at it. Yeah comparing itself … I added the IsParralel.pop(0) already, but your suggestion is more solid!
Not sure if it helps since you wanna go python, but surface.normalatparameter and vector.almostequalto should do the trick with nodes.
