how to display plant root system

[Lianhai]

I need to show a 3D plant root system in my application. The data describing the system (including location, radius, segment numbers of neighbours of each segement) is stored in a database. Whenever I tried to smoonth the linkages among segments, I failed to do so. There are some gaps between segments.
Could you out there please help me to tackle the problem with some codes or pseudo-codes?
Thanks