 # Inflection points with GhPython

Hello
Using curvature and intersection give close result but intersection always need to check the new curvature curve
The script created by @dale work fine but i don’t understand how to convert it to python looks like it use looping

If you’ve access to Rhino 7 WIP, you can use Curve.InflectionPoints and Curve.MaxCurvaturePoints like this:

``````Inflections = c.InflectionPoints()
MaxCurvature = c.MaxCurvaturePoints()
``````

MinMaxCurvature.gh (5.1 KB)

1 Like

Thanks , i see this in your post from other thread and it give the same result as @dale script.
There are different way with regular components but at the end all need intersection,
and it is for v6

There is a component from the old forum created by Walter Zesk
based on vb code of @DavidRutten

Which also available from archive web

give exactly the same result as script @dale

## The explanation is not clear to me, can this done by regular components?

Update, after testing visual code with very small curve it fail

I try to convert c# code to python without success; i got null points

conversion c# test2.gh (8.5 KB)

A new try, it give similar result but not the same 100%

``````points = []

def GetInflectionPoints(curve, points):
if not curve: return
nurb = curve.ToNurbsCurve()
if not nurb: retrun
on_zero_tolerance = 2.3283064365386962890625e-10
count = nurb.Points.Count * 1000
mul = 1.0 / count
if nurb.Domain.Length > 1.0:
epsilon = nurb.Domain.Length * on_zero_tolerance
else: epsilon = nurb.Domain.Length
t0 = 0.0
k0 = Vector3d.Unset
start_set = False
for i in range(count):
t1 = nurb.Domain.ParameterAt(i * mul)
k1 = nurb.CurvatureAt(t1)
if k1.IsValid:
if k1.IsTiny():
continue
if start_set:
t0 = t1
k0 = k1
start_set = true
continue
if k0 * k1 < 0.0:
pt = Point3d.Unset
t = (t0+t1)*0.5
k = nurb.CurvatureAt(t)
if k.IsValid:
pass
if k.IsTiny() and t1-t0<epsilon:
pass
if k*k0<0.0:
t1 = t
k1 = k
if k*k1<0.0:
t0 = t
k0 = k

pt = nurb.PointAt(t)
Finally 