Join the GTA IV Modding Discord Server if you need help, we also have more tutorials on our server: / discord
This process also works for other 3d maps you want to convert on 3ds max.
And luckily you find here a copy of Pixelactive Cityscape 1.8 which company got sold and that Promotion copy was hard to find on the web.
Links!
Cityscape 1.8 https://drive.google.com/file/d/1NpXA...
https://archive.org/details/CityScape...
3ds max https://www.autodesk.com/ ( I suggest you to get 3ds max 2012 since its compatible with all current IV tools, its only available through p1rating, search around for a crack)
OpenIV http://openiv.com/
GIMS IV https://gtaforums.com/topic/474215-gi...
This tutorial took me 1 day to make and i really put effort into it. Stay turned for more little GTA IV Mapping tutorials!