I reached out to the author a few days ago and he sent me the source code for Populate:Terrain. Anyone interested in updating it for max 2019?
I think the problem is that the Normalize_Spl modifier has been replaced. See this forum post:
This would obviously be release free of charge. Maybe open source, on GitHub? I don’t script but will coordinate.
Thanks,
Caleb
That is so odd and I am sorry that it isn’t working for you.
OK Bobby, now try it with a decent amount of contour lines and a higher rez, like 100 x 100. Worked in 2018 but hangs in 2019 on my both my computers.
Oh, I use it all the time on very heavy scenes. In MAX 2018 it wasn’t working good and failed a lot, but no problems in MAX 2019.
@glorybound I’ve noticed that you are using an old version (1.2) so that might be the reason? I have a newer version ( v1.86 ) (Max 2019.3) and it works on simple cases but as soon as I have multiple shapes inside each other with different hight max will crash with a message that mentions runtime error and Normalize spl.
it would be great if you could upload your copy so I can test it .eventho the new version has more features I could live without it if I had to.
Edit: I found a copy for 1.2 and it is still causing a crash in the above-mentioned cases 
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I have basic knowledge in Maxscript and I did few scripts for my personal use so I might be able to help here.
PM please with a link so I can take a look.
I did upload it, if you look back in the tread where we are discussing the same thing the other day.
Yes, sign me up. I’ll also take a look at the code
Yes, I’ve tried it and unfortunately, Max Crashed too ..try the following steps :
1-create 2 circles shape lets say 100cm and 50 cm in radius at [0.0.0]
2-move the inner circle up in the z-direction 20 cm
3-convert one of them to editable spline and attach the other
4-use Populate: terrain and max will crash
Confirmed
Okay, thanks bobby
I’ve found the issue and I’ve fixed it with the help Caleb .will do proper changelog, comments..etc and post a link here for the update.
Any update? I am in need of it 
Hey all, here is the script:
Thanks to M.Max for the fix!
Awesome! I’ll try it today.
something doesn’t look right on the code up left (this is not how it should looks )
Please check the one in the attachment below
if you still have an issue then uploading the max file might help to figure out what’s going on here.
populate-terrain 1.87.rar (57.9 KB)
I can’t download that file. It gives a network error.
Try this link
Downloaded and I’ll give it a try.
Yep, perfect!
could you please show how to reproduce that? I’ve tried different combinations and it worked just fine here. (Max 2019.3)