Projecting Rays from screen(frustum) to select objects

What is the best way to select characters(objects).
Usually one can project a ray from frustum. Is this possible with this sdk?

Yes, you can pick. Question already answered. Please search forum.

4 choices:

1. Color picking (default SIO2 method which is optimal for iPhone)

2. Physic Picking (true ray cast in 3D)

3. sio2Project / sio2Unproject (depending on what exactly you want to do)

4. Implement your own picking method similar (check the Mesa source for the way GLU is doing it)

5. ?????

Ok I want to get the X,Y,Z coordinate of a plane so that I can send an agent to that location, ideally i wanna find the node closes to that position and initiate an A*.

So I am guessing ray casting would be expensive. I would like to not use bullet if possible. What are my options.

Also why am I getting _SIO2transform->dir always zero.
I print out the x,y,x values after rotation and transformation but still i get zeros for direction.
And does the direction represent the facing vector? Or if not what does it represent.

Thanks for the feedbacks by the way. More I dig into the sdk the more I enjoy it.

Ray casting is not that expensive if you don't have too many...