Hi, I'm working through the guides and sample code on Apple's site to learn iOS development, I think I'm getting the hang of the basics but this one has me stumped. I'm trying to do a simple transition between two images, I've built the sample project fine, and I've copied the code into my own project with other stuff, but I'm getting the error 'CATransition undefined' when I try to build. I'm assuming this is because I haven't included a framework properly. I have #import <QuartzCore/QuartzCore.h>, which is the only reference I can find in the sample project to import any frameworks. I noticed that I didn't have 'QuartCore.framework' in the frameworks directory of my project, but it is there in the sample project. I tried to find a 'proper' way to include it, but failed (the guides/forum help on google are all pre xcode4, I don't know if this has changed but I just couldn't follow those guides). So I dragged it across from the sample one, but it made no difference. Is there a proper way to add that framework to the project, or am I just totally wrong about that being the problem? Cheers!