Many times when you attempt a large render you'll get an "out of memory" error. This will happen variably depending on the complexity of your scene. In other words, the more complex your scene, the more limited your render size. However, by using the "select render area" option you can have renders of unlimited size. When using "select render area" for a final render you must render to screen. In the resolution fields, enter the final dimensions of the image you want. Vue will calculate the size of your selection in relation to your overall requested render size. In a nutshell, the concept is to have Vue render smaller pieces of your image which can be re-assembled in a program like photoshop later. Divide your picture up into as few pieces as your memory can handle with plenty of overlap.