how do i place a block perfectly beside each other in fps like this as shown on this video click the link. when your done watching the video you see how he places the blocks perfectly beside eachother in this game i want that in my game how do i do that.
http://unity3d.com/support/documentation/Manual/Instantiating%20Prefabs.html
You can code it so that it makes it, look at the first segment of code.
You can use vertex snapping (hold down v, then click on a vertex on the block that you want to move, and then drag it to the destination vertex).
See a video of the feature here: http://blogs.unity3d.com/2010/04/23/unity-3-feature-preview-snapping-marquee-selection/