Lego Digital Designer is a nice piece of software used to make virtual Lego models. The software is designed and made by Lego, so there is no problems.There are three modes.These would be further explained in this Instructable, which I'll do.
Step 1: The Palette Select Menu
This menu comes up when you start LDD.This menu is where you select which mode to use. They all omit certain pieces though.(For example,do not expect bricks in the Mindstorms mode.)
THE THREE MODES
The Factory ModeThis mode allows you to check how much your model would cost in reality. I also think that you can buy it as a kit,but I am not so sure about that. I will check it.
The Mindstorms ModeThis mode gives you the limitation of the parts that make up one NXT kit. You can make a robot.I made a robotic trike. As the name clearly indicates, mindstorming should make a good robot.
The Creator ModeThis mode contains the parts that are in Creator kits. The name is a good choice,again. I like this mode. I don't know why.
Step 2: The Brick Palette and the Toolbox
These are the most important parts of LDD.They contain the parts and tools. The Brick Palette has useful filters.If you want to make lots of the same part,I suggest the Clone Tool.
THE BRICK PALETTEThis is where you get parts.You can get as much parts as you want. The parts are organized in groups.
The Components Of The Brick Palette
The Collapse Dividers ButtonThis button makes all open groups close. Useful and saves you a lot of scrolling.
The Hide Colors ButtonThis button hides same pieces with different colors.You get to pick the color when you mouse over the part.(see picture)
The Box Filter ButtonThis button brings up a menu which you pick a kit,and it limits you to the parts of that kit. Sometimes useful.
The Color FilterFilters parts by color. Simple.
Remove Filter ButtonThis button removes all filters, including the mode limitations.I press this before starting.
Step 3: More Modes! Isn't This Overwhelming?
Here we will focus on the View,Build and Building Guide modes.They are useful,as you guessed.The build mode is where you build your model(:P).Then you can go to the view mode which puts your model on a background.The build guide mode makes an animated guide on how to build your model.You place bricks by clicking them in the brick palette.
Build ModeThis is where you make your model.
View ModeYou can watch your model and blow it up.Don't worry,it heals back up.If you made a train,you can animate it.(The train and tracks are under robotics.)
Building Guide ModeThis generates an animated guide on building your model.You can make it HTML too,but that doesn't work for me.
Step 4: Camera Controls
These controls are very useful. Especially when you need to change the angle of view.This is very simple,except one thing. The controls are reversed. Right makes left,and vice versa.Up makes down,and vice versa.Plus zooms in,and minus zooms out.
Step 5: Finally,the Toolbox!
This is the last important aspect of LDD.This is where your tools go.It can be minimized like the Brick Palette.
Select ToolThis tool selects objects. :) When you click it,it also gives you options.I like the Group Select for moving large groups.
Clone ToolMakes an exact copy of your piece.Then you place the copy like a brick taken from the Palette.You can multiple select by dragging the mouse.Anything completely inside the box it draws will be copied,and have a cyan border while dragging.
Hinge ToolTurns your piece with any piece solidly attached to it.For example,you can hinge a Technic piece if it is attached to another with one snap or axle.It turns the other piece if they are attached with two snaps or axles.
Paint ToolChanges the color of a piece,if possible.
Delete ButtonRemoves pieces from the model.
Step 6: Wrap-up
Here,I told you how to use LDD.I think this program should be owned by every Lego fan who can't buy any.This is not full LDD,it takes experience. Ask me via comments or PM if you have problems.I prefer comments because then other people with the same problem can learn the solution. I will also accept PM's.