Please tell me about this features ( blend & network )

 From:  Michael Gibson
906.2 In reply to 906.1 
Hi Lish, use Blend to create a new piece that makes a smooth connection in the empty space between 2 existing pieces. You can use it on either curves or surfaces.

Use Fillet when things are actually touching one another - Fillet will trim back areas to make space for the radius that you request.

Blend is used when things are not touching but you wish to connect them together.

Here are some examples:

Network is used to create a surface from a grid network of curves. It is similar to loft, but basically does a loft simultaneously in 2 directions, so you can gain additional control over the shape.

See here for some more info on Network:

Hope this helps!

- Michael