Write some Software Need a C# function/object to plot an orbit

I need a C# Object that will give me the points on a simple elliptical orbital path involving a single large mass and a small object - sun and planet type. The input is 1. the width and height of the ellipse that defines the orbit in km 2. The mass of the center object in kg The available data that are computed from that are: 1. The time it takes an orbit to complete 2. The eccentricity of the orbit Then I want an entry point that lets me do this: [login to view URL](double TimeSincePerihelion,out X,out Y) I need the total time it takes for an orbit to compute the steps. I would iterate through this call to get as many points as I need. where X and Y are relative to the foci of the ellipse. In the case of a large mass this would be the center of it. The values of X and Y would range from -,- to +,+ 0,0 is the foci/location of center mass I actually found something that does just this here: [login to view URL] but when I coded it up it didn't produce the values I was expecting and I lack the depth to diagnose the issue. I need someone that understands the math. This should probably be a class with the constructor taking the mass and size of the ellipse and a PlotPoint method to get a point. thanks