Does anyone knows a good efficient method to export rendered 3D model to Isometric view?
I would also like to hear some suggestions what kind of 3D Modeling software are the best and user-friendly.

I appreciate for the time and help! :}

You're not looking for an 'export', you're looking for 'render'. And any 3D modeling software worth a damn will allow you to render.

Thanks, that was quite what I was searching for, however it's not pixel-accurate camera.

Something that would work with this position formula :}

x(screen) = x?z

y(screen) = y + (x + z) / 2

You're not going to find any 3D modeling package that uses your formula behind the scenes. They will all use a general-case transformation system. The best you can do is set your camera to approximate your formula.

For one thing, your coordinate space is distorted. From looking at the (x-z) and (x+z)/2 portions, I am led to believe that the camera angle being represented is to implement the standard 2:1 tile size ratio, which is approximated by a 30 degree camera view. ie, 30 degrees above horizontal. However, the +y portion of your y coordinate calculation doesn't take into account the foreshortening of the y axis, so objects are skewed, with y contributing too much to the final screenY coordinate. More proper would be to scale y's contribution to the screenY by sin(30) to approximate the foreshortening.

That being said, just use an orthographic perspective as 3DModelerMan suggested, and set the angle of the camera above the horizontal to be 30 degrees. The resulting render should be close enough for government work; any inaccuracy may need to be corrected with Gimp or Photoshop.

this is what you need to do.

http://clintbellanger.net/rpg/tutorials/isometric_tiles/