Tween curves problem

Hi everybody,

i am trying to tween 3 curves
the result is not 100% correct (see jpg).
It would be great if someone could tell me why this is happening and how to avoid it.

I have attached the script.

thank you!!!

tween curves (18.8 KB)

Do everyone a favor, and work near the origin. Nobody want to search your curves in the universe :smiley:

And when i open your file, there are just 3 curves and they are the same. Can you reupload it?

May @Michael_Pryor can see what happend here, it’s his plugin.

Hi Tim

i have uploaded the file again using the standard tween component.
the tweened curves in the highlighted areas (margenta) don’t look correct.

tween curves (5.2 KB)

Take the pufferfish component, the native for example doenst work with polylines etc.

When opening your file, there are still just 2 curve, really large and in the same y.

But heres an example:
You can look at the polyline tween, they are right. Than compare the nurbs tween with the polyline(with fillet). I think polyline with fillet Looks better. But I don’t know how your curves are created. May this be a solution. May when i finally can open a file of you, we can find a solution.

tween curves (7.1 KB)

hi Tim,
thank you for taking the time to check my script!!!

I dont know why you cant view my file.
I internalised the curves.

The re uploaded version was just showing two curves which is correct.

Your tweens look exactly the way they should, unlike mine as you can see on the jpg.

I guess the big difference is that I
drew curves and filleted them in rhino and referenced them into two curve components in grasshopper.
and thought that I would get a clean result using the tween component in grasshopper
which is not the case.

Thanks anyway.Learned something new thanks to you.


Fillets don’t really tween great at first because they are arc, which means they are degree 2 curves with minimal control points and the shape comes from various weight values on the control points. Degree 2 curves usually like offsets better over interpolation. The fix usually is to first fit curves with fillets, which gives the fillet much more control points based on curvature (better for tweening since tweening is about curvature). You should use the most updated Pufferfish which has a better code that accounts for fillets as it automatically fits them, and also has a refit option (not need in this case but useful for some trickier arc conditions)

Nice to know. Thanks :slight_smile:

thank you Michael and Tim.
Really appreciated both of your comments.

lesson learned!!!