Origin Version (Select Help-->About Origin): 7.0 Operating System: win XP
I try to use the interpolate function in Origin 7.0. According to its help, the interpolation is done with the same method of point connection: straight, B-Spline, Spline.... But I always got the interpolation with the straight line connection even I choose the Spline in the drawing.
I've figured it out. If the graph is graphed using partially in the middle of a dataset, it has this problem, interpolating with straight line no matter what the connection type (B-spline, spline etc.) one chooses.
To solve my problem, I simple copy the data out from the whole dataset to graph.