: Select all your height-stepped splines and go to Create Panel > Geometry > Compound Objects > Terrain .
1. Forest Pack by iToo Software (The Industry Standard for Scattering) 3ds max landscape plugin
The 9.3 release introduced several workflow enhancements. Distribution images can now be interpreted as gradated density maps rather than simple black-and-white masks, providing much finer control over vegetation placement. Painting areas has become more intuitive with modifier keys (Ctrl to paint, Alt to erase), and a new option to randomize scale by area allows vegetation near edges or paths to have different scaling from denser interior zones. : Select all your height-stepped splines and go
: A newer tool for creating realistic climbing plants that crawl up structures in near real-time. Alt to erase)