Hello.

it is possibly that i write it incorrect and you can't understand me. Here I created image showing what i trying to do:

I got red dots as polyline points. It is easy to create line through this dots. But i need to create polyline with width so I need to create it using triangles.But when i directly create it using only right vector i got errors on curves. Is there any algoritmic way to find vertex points for green triangles?

Ah, I see what you mean. Is this a 2D strip or a full 3D "tube"? I'll tackle the 2D solution now, and then we can extrapolate to 3D as necessary.

The key is that the red points define a line through the center of your strip, and that at each joint the red point is the center of a cross-cutting line whose adjacent angle is precisely half the deflection between the segments. So, starting from the left of your diagram and numbering the red points *p1*, *p2*, *p3* and *p4*:

- at
*p1*there is no previous segment, so our strip's ends are perpendicular to the vector <*p2 - p1>*; - at
*p2*the cross section is at an angle relative to <p2 - p1> that is precisely half the angle between*<p2 - p1>*and*<p2 - p3>*; - at
*p3*we have no next segment, so our strip's ends are again perpendicular to the vector, this tome*<p3 - p2>*.

Remember that perpendicular lines have slopes that are the negatives of each other.

Using the above, you should be able to generate the points in your strip. Be careful in your algorithm to maintain the correct vertex order. I'll check back in a couple of days to see how you made out.