Many curves derived from sectioning a BREP, unpredictable outcomes

SubCurve 01.gh (12.1 KB)

Your curves parametrization is undefined. For example, the start point not always is at parameter 0:

Reparametrize your curves.

Thanks for the reply but this is not the issue.

Curve #37 for example is the second curve in the example below

SubCurve 02.gh (13.7 KB)

As you can see, PCX performs as expected when there are just 3 curves, but when the entire model is fed in, 3 or 4 curves have odd t values

( i cant upload the entire model)

as you will note, I have ensured all curves have the same direction (down)

I cant explain it

Curve parametrization is a thing.

If you use sub curve with a domain “x to 0” it means you are expecting your curves to have a parametrization such that make the end or the start of the curve at t=0.

Direction is not related with parametrization, in this context.

Your last .gh attached have no problems here… but it have just 3 curves… if you have a situation where, even with reparametrize, it is not working, attach that please.

I spent all day working on this. I made a model I could upload to demonstrate the problem, but it is working fine.

Found the problem. One of the curves does not intersect the plane and when the list is flattened, everything is off.

Now I need to figure out how to insert 1 where there is a null

There is “Replace Nulls” component.

You can also consider about extending all the curves so the intersection happens everywhere…

Edit: your is not a null object… but an empty branch.

Do insert item at index 1, then split list at 1… this way every branch have an element added, and then every item past the first is removed.

Thank you for your patience )