I have a model which has already layouted uvs. I have to readjust small part of it in the modeling process. Soi deleated few faces and extruded new faces . When i want to automap the new part of the model nothing happens - in the uv texture editor there is simple square with 4 uvs although the faces of the new part is about 50 faces . How to map this part ?

If you extrude a polygon, it tends to have all the UVs piled on top of each other, like a stack.
You can lay them out by selecting a face, converting your selection to UVs, and move those UVs elsewhere on the map. After you have all these separate shells laid out, you can combine them.

This is tedious, but it will rescue your UV map, should you have a lot of time invested in making it. Or you could just use something like Automatic Mapping to make a new UV map, and scrap the old one.

<* Wes *>

Thanks dude. I unfolded the squre , cuted all the faces because they were mess and solved all manually the uvs are now good . Could they create any further problem after zbrush , rigging , animating and rendering ? I don’t want to make any further work on this model until i am sure that this is already flawless finished.