I am using 3DPlot Utility for Surface Generation. In my case, the y upper limit is a function is current x value. Can anyone help solve this problem?There is an simple form of my problem0.1 < x < 0.50.1 < y < 2*x(defun z (x y) (list x y (+ x y)))How should write the code for 3D plot (3Dplot z 0.1 0.5 0.01 0.1 '?' 0.01)Thank you

If I understand this correctly, you can just modify your Z function so as Y does not go over 2*X. E.g. this way: (defun Z (x y) (list x (min y (* 2.0 x)) (+ x (min y (* 2.0 x)))))  

Thanks for your suggestion. your answer solves half of the problemWhat should write in place of '?' (upper limit of y) in 3Dplot code(3Dplot z 0.1 0.5 0.01 0.1 '?' 0.01)Should I have to replace it by 2*(0.5) (ie., 2*max of x)?Also in your solution, The values that are greater than 2*x become same pointsAnd I think it might change the curvature.Is there an option to not to consider those points Thank you

It depends on what the max. value should be - probably just 0.5. Due to the meshing algorithm used it is currently not possible to completely skip/omit nodes.