3rd party application for creating towns????
 

Hello! I want to create a whole town from scratch (with playgrounds, mountains, park, road), export it to a file and later load it in vizard.
Please Could someone tell me what the most suitable 3rd party application that I could use?

Take a look at the following knowledge base article:

http://kb.worldviz.com/articles/1413

You could try combining different models from Google's 3D Warehouse into one scene in SketchUp. Then you could export that to the Collada format and load it in Vizard.