类型错误：+= 不支持的操作数类型：'int' 和 'NoneType

Question

I need the edges of the object to be painted in color. I know python very poorly, but my teacher gave this code and this is what happened with it.

def triangleArea(half_edge):

    a = len (half_edge)
    b = len (half_edge.edge_next)
    c = len (half_edge.edge_next.edge_next)
    
    s = (a + b + c) / 2
    area = math.sqrt(s * (s - a)*(s - b)*(s - c))
    return area

def angle(half_edge):
    
   v1 = half_edge.vertex
   v2 = prev(half_edge).vertex
   v3 = half_edge.edge_next.vertex
   
   angle = math.acos(((v2.co.x - v1.co.x)*(v3.co.x - v1.co.x)+(v2.co.y - v1.co.y)*(v3.co.y - v1.co.y)+(v2.co.z - v1.co.z)*(v3.co.z -v1.co.z))/(len(prev(half_edge))*len(half_edge)))
   
   if (angle > math.pi / 2):
       print (">90")
       return angle
   
def curvature(v):
    anglesSum = 0  
    completeArea = 0
    for e in h_edge_list:
        if (v == e.vertex):
            start_edge = e
            anglesSum += angle(start_edge)
            completeArea += triangleArea(start_edge)
            
    half_edge = start_edge.edge_next
    cur = (2*math.pi - anglesSum)/completeArea
    color (half_edge, cur, 0.13, 0.29)#farbime z intervalu 0 az 2/3
    return cur

for e in h_edge_list:
    print (curvature(e.vertex))
      
bmesh.free()  # free and prevent further access

error in the last lines of code with the S operator enter image description here

Answer 1

Your angle function returns None when this condition is False

if (angle > math.pi / 2):
   print (">90")
   return angle

This is how return in your current angle function looks like

def angle(half_edge):
    
   v1 = half_edge.vertex
   v2 = prev(half_edge).vertex
   v3 = half_edge.edge_next.vertex
   
   angle = math.acos(((v2.co.x - v1.co.x)*(v3.co.x - v1.co.x)+(v2.co.y - v1.co.y)*(v3.co.y - v1.co.y)+(v2.co.z - v1.co.z)*(v3.co.z -v1.co.z))/(len(prev(half_edge))*len(half_edge)))
   
   if (angle > math.pi / 2):
       print (">90")
       return angle
   return None

It returns None if the (angle > math.pi / 2) condition is False

Maybe you want to return the angle value, whatever the condition is (this makes the if statement unnecessary), by reducing its indentation tab

def angle(half_edge):
    
   v1 = half_edge.vertex
   v2 = prev(half_edge).vertex
   v3 = half_edge.edge_next.vertex
   
   angle = math.acos(((v2.co.x - v1.co.x)*(v3.co.x - v1.co.x)+(v2.co.y - v1.co.y)*(v3.co.y - v1.co.y)+(v2.co.z - v1.co.z)*(v3.co.z -v1.co.z))/(len(prev(half_edge))*len(half_edge)))
   
   if (angle > math.pi / 2):
       print (">90")
   return angle

Answer 2

This if statement will return None if this condition is False

if (angle > math.pi / 2):
   print (">90")
   return angle

You'll want to add at least an else statement to your angle function.

Answer 3

The angle function is returning NoneType if the condition inside is not satisfied, and the += operator can't be used with NoneType values. Try returning 0 instead.

if (angle > math.pi / 2):
    print (">90")
    return angle
else:
    return 0