I have set of points. I created strip triangles using these points.
Now I need to calculate normal. What I thought that for each triangle there should be a normal. But function I am using says that for every point there will be a normal. I used three points to calculate normal of a triangle, but how can I calculate normal of a point.
So if am using the example shown in the figure what will be normal of All points (A, B, C, D, E, F).
In your case, the normal line at each point is the same line translated in the plane through the triangle. Just like for a curve you have the tangent line to the curve at each specific point, and tangent vectors within the tangent line, curves also have normal lines, and normal vectors within those lines. Both lines require an origin to define vectors properly, and that origin is the point at which the line is normal or tangent to the curve.
In your case, you wouldn't see any difference between the normal lines at each point on a triangle, because it's flat.