Irrlicht Engine

Hello again. Thanks for all who help me yesterday, you are the best!
How can i check for collision with 2 3ds-models? And with 2 cubeSceneNode's ?
Be sure, i read tutorial about collision, but answers for my questions (in my opinion) in this tutorial was not explained well.

And second question: Can ...

thanks!

thanks!!

maybe you now, how i can rotate (not animate) camera around it self (if player in game bend his head on side)?

i use this code:
scene::ICameraSceneNode *camera = smgr->addCameraSceneNode(smgr->getRootSceneNode(),core::vector3df(100,100,100),core::vector3df(0,0,0),-1);
camera->setRotation ...

i want to use png-texture with transparent and semi-transparent zone for billboard and cube nodes?
if i use only:
video::ITexture *frame0=driver->getTexture("media/car.png");
billboard->setColor(video::SColor(255,255,255,255),video::SColor(255,255,255,255));
billboard->setMaterialFlag(video::EMF ...