I believe this is what you want. Replace 21 by 3. xcoor = Range[1, 2, 1/20]; ycoor = Range[3, 4, 1/30]; coor = Tuples[{xcoor, ycoor}]; points = Partition[Flatten@Thread[{coor, Total /@ coor}], 3]; ListPointPlot3D[points]

This is exactly I was looking for thank you.

Is this what you are looking for? coor = Tuples[{Range[1, 2, 1/2], Range[3, 4, 1/2]}]; ListPointPlot3D[ Partition[Thread[{coor, Total /@ coor}] // Flatten, 3]]

Okay maybe I did not pose the question well enough. xcoor = Range[1, 2, 1/2]; ycoor = Range[3, 4, 1/2]; (x + y /. x -> xcoor) /. y -> ycoor I want to be able to plot the matrix as data point with respect to xcoor and ycoor. Each point in the matrix has corresponding coordinates. I can't use the function directly (in this example x+y) . I have to use the matrix values.

3D List plot from a 2D array (Matrix)?