3ds max is a professional modelling application with many features that are conducive to making models for Urban Terror.
- Exceptionally mature with a lot of must have tools built in.
- Plugins for inport and export of .ase models
Blender is an open source modelling program.
It may be hard to get into it, but it is a very useful application.
Misfit Model 3D
Misfit Model 3D is an OpenGL-based 3D model editor that works with triangle-based models. It supports multi-level undo, skeletal animations, simple texturing, command-line batch processing, and a plugin system for adding new model and image filters. Complete online help is included. The primary design goal is to be easy to use.
Misfit Model 3D was written and tested on Linux (2.4 and 2.6 kernels) and has been compiled and tested on most major Linux distributions. It is also known to run on FreeBSD, Windows XP/2000, and Mac OS X (experimental).
Misfit saves in md3 format.
A very easy to use 3d tool, no longer in development but the 1.36 development version is very complete, as a simple modelling tool.
There's an excellent tutorial (tree) [here]
Or try this tutorial - how to make a simple lightbulb model.