ios有3D旋转的视图用下面的代码截不出3D效果来呢，哪位高手指点一下啊

Question

-(UIImage *)captureView:(UIImageView *)imageView
{
    //Merge the two images.
    UIGraphicsBeginImageContext(backgroundImageView.frame.size);
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    [imageView.layer renderInContext:ctx];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}