Subtracting allows complex objects like a rectangle with a hole through it to be made.

Intersect is used for when 2 objects are drawn over each other and the part(s) where the objects overlapped are kept.

Union:

In this picture, I have 2 rectangles, a wedge and a cone:

Selected, the lines would appear like this:

Now that looks really messy doesn't it? To change this, select the union tool OR type “_union” then select all the objects:

Then we press ENTER. All these objects will become one big object:

Subtract:

In this picture, I have a normal rectangle:

Now I'm going to draw another one intersecting it:

I'm going to make a rectangle with a hole through it like a hole for a door. In order to do this I could draw a lots of rectangles or I could simply use the subtract tool. To do this, click on the subtract tool or type in “_subtract”.

There is a certain order you must select objects. Select the object you are going to subtract FROM, in this case the taller rectangle. Then you press ENTER. Now you select the object you are going to use to subtract, here it is the smaller rectangle. Then you press ENTER and you are left with this:

Intersect:

In this picture I have a sphere and a rectangle intersecting:

For some odd reason I want the part that is overlapping ONLY. To do this, select the intersect tool or type “_intersect”. I then select both objects and press ENTER and I'm left with this:

I hope you have learnt something from this tutorial!

Note: If you accidentally select the wrong object, you can unselect it by holding SHIFT and clicking on the selected object.

Let's say we drew a 3D rectangle and we accidentally made a mistake by drawing another rectangle that intersects it:

To fix this, select the erasing tool from the tool palettes OR type “_erase”:

Next we select the object(s) we want to erase by clicking on them:

Then we press the ENTER or RETURN key, which ever one you have on your keyboard.

Problem solved - There is also another simpler way to do this. Simply click on the object you want to delete:

And press the DELETE key on your keyboard! You may think this is simple, but it took me 30 minutes to figure out how to erase when I first started AutoCAD so this is why I decided to make a tutorial on it.

The command window is, as the name suggests an alternative way to interact with AutoCAD. You can enter commands within the command window, such as “_move”, “_erase” etc. It also acts as your history, as it displays all your previous actions. It is possible to draw complex objects without using the mouse.

Anyways I will demonstrate a command window function; here I have drawn a 3D rectangle:

I want to move it without using the mouse, so I type in “_move”, it will appear under your mouse cursor, so don't worry:

Then I press ENTER.

Here the command window displays “Command: _move”. This means that I have used the “_move” command. Now I select the objects I want to move and press ENTER:

Now it asks for a base point or an alternative. The base point means the point that the object is going to be moved from. In this example, I would just type in 0 and press ENTER. Now it asks for a 2nd base point, for this example, input anything and it will move there or simply use the mouse.

And there we have it, the command window in action!

Note: Sorry if my tutorial was a bit vague, the whole point of it was to say that the command window is useful.

AutoCAD is a program used for 3D modelling, usually for landscapes and building plans etc. In this tutorial I will be teaching you how to extrude. I assume you know how to draw 2D and 3D objects, if not just play around with the tools (it's really easy, trust me). I will be using AutoCAD 2007, a slightly newer version but it shouldn't make too much of a difference.

Extruding:

The extruding tool in AutoCAD is used mainly for adjusting the height/depth of an object. In here, I have drawn a 2D rectangle; it may be hard to see:

Right now, the rectangle doesn't really *exist* and it cannot be rendered. But we will change that.

This is the extrude tool, it is located in the “3D make” control panel:

To extrude the 2D rectangle, I would click on the extrude tool and then click on the rectangle:

Once I have clicked on the rectangle, I would then press the ENTER key on the keyboard. Doing so would enable me to extrude the 2D rectangle, here I can physically adjust it myself using the mouse or I could input a value to extrude it to:

Once you are satisfied, click the mouse to make the changes or press enter if you inputted a value. Now you made a 2D rectangle into a 3D solid. To render, go to View > Render > Render.

This is what it would look like in render mode:

Note: Extruding is not just limited to rectangles.