Making
the Leap
from AutoCAD to Autodesk Inventor
10 Easy Steps from
CADENCE Magazine Columnist
Lynn Allen

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Making the Leap from AutoCAD
to Autodesk Inventor
So here I am, one of the biggest fans
of AutoCAD,® writing a booklet
on Autodesk Inventor®.
Why would I want to do that?
Well, I must admit I was skeptical at first that this 3D modeling product could
really be as easy and powerful as everyone said it was, not to mention the fact
that Autodesk Inventor isn’t even based on AutoCAD! What about all those
years of AutoCAD knowledge I’ve acquired? How could I possibly draw faster
in any other CAD package than I do in AutoCAD? In this booklet, I hope to
convince you that, believe it or not, it’s actually easier (and faster!) to draw in
3D Autodesk Inventor than it is in 2D AutoCAD. I’m a believer, and I hope to
turn you into one as well.
This booklet is intended to be an easy read and a friendly introduction to the
world of Autodesk Inventor. Delivered in 10 easily digestible doses, it covers the
basics in a way that I hope makes you feel comfortable taking your first steps
into this robust and exciting 3D modeling package. You’ll even discover that if
you aren’t ready for the world of three dimensions yet, Autodesk Inventor is an
amazing 2D program as well. The parametric modeling capabilities in Autodesk
Inventor kick the IQ of the program up so many notches you’ll find that it does
much of the work for you! In fact, Autodesk Inventor is so smart and so easy to
use that you’ll keep thinking there must be a catch (I certainly did!). There’s no
catch—it’s just a remarkable program that’s built on tomorrow’s technology.
And why shouldn’t it be? It’s written by the company you’ve trusted with your
designs for over 20 years—Autodesk!
So let’s begin our journey into the world of Autodesk Inventor software…

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1
Discover the Difference
Between AutoCAD
and Autodesk Inventor
A
B
There are many differences between AutoCAD and Autodesk Inventor soft-
ware. We’re going to take a look at five of the biggest and most apparent dif-
ferences between the two products to make sure we’re off to a good start.
A
AutoCAD is “geometry-driven design”; Autodesk Inventor is “dimension-
driven design.”
In AutoCAD, we create our geometry and then place our dimensions. If we
make changes to the existing geometry, the associated dimensions update
(hopefully!). Wouldn’t it be nice if you could change the value of the dimen-
sion and drive the shape and size of the part?
Well, that’s exactly how Autodesk Inventor works. You roughly sketch the part
you want to create, and then you control the exact size and shape of the part
with dimensions. Imagine how easy it would be to make changes to your part
later by simply changing the dimension values. Need to change the length
of a plate from 30 mm to 35 mm? Simply change the dimension! Why does
Autodesk Inventor work this way and AutoCAD does not? Autodesk Inventor
has the added intelligence of being a parametric modeler.
Autodesk Inventor is a feature-based modeler.
As you create your 3D parts, each extrusion, hole, chamfer, fillet, and so forth,
is stored as an independent feature in the Autodesk Inventor browser. This
makes it extremely easy to make changes down the road. If you decide that

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hole should have been 10 mm instead of 12 mm, it’s not a problem to make
the change. In AutoCAD we often find ourselves deleting and re-creating a
specific feature. Such changes in Autodesk Inventor are as easy as changing
the dimension value.
Autodesk Inventor supports adaptivity.
One of the features that separates Autodesk Inventor from other 3D modelers
is the ability to create adaptive parts. These smart parts maintain a physical
relationship so that if you modify the geometry of the base part, the adaptive
geometry knows to update as well. This could be as simple as creating a hole
that adapts to the size of a rod. As you change the size of the rod, the hole
gets larger or smaller to accommodate the new diameter of the rod.
Autodesk Inventor doesn’t use layers!
There, I said it—and if you can handle that concept, you’re a prime candidate
to learn Autodesk Inventor. Let’s face it, none of us really likes dealing with lay-
ers in AutoCAD, but we’re forced to because of linetypes, lineweights, and so
on. What if you could set up all your parameters once and have Autodesk
Inventor automatically assign them to your parts from that point forward? Let
the software do those tedious chores for you so you can focus on the impor-
tant aspects of your design.
B
Autodesk Inventor was built specifically for the manufacturing industry.
AutoCAD was built (nearly 20 years ago) to be all things to all people. It must
take into consideration the needs of all disciplines: AEC, Civil, FM, Plant Design,
and so forth. Autodesk Inventor was created with one and only one industry
in mind—Manufacturing. From the ground up, Autodesk Inventor was built to
think the way you think and act the way you expect it to act.
Last but not least—repeat after me—Autodesk Inventor is not AutoCAD!
You will have a much happier life if you realize this early on and don’t try to
equate the AutoCAD world and processes to Autodesk Inventor technology.

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2
Get Comfortable with
Autodesk Inventor
A
B
First and foremost, you need to feel comfortable in the Autodesk Inventor envi-
ronment. Let’s take a quick tour of the user interface and point out some of the
similarities with and differences from our familiar AutoCAD environment.
A
What happened to my command line?
We depend on it in AutoCAD. In fact, to some of us it’s practically a religion,
but in Autodesk Inventor you won’t even miss it. We don’t use “commands”
in Autodesk Inventor, we use “tools.”You can easily access each tool from four
different areas—pull-down menus, toolbars, context-sensitive shortcut menus,
and the panel bar. Of these, only the panel bar should be unfamiliar to you.
While AutoCAD still relies on countless keyboard options for many com-
mands, here you’ll find a variety of friendly, dynamic dialog boxes to input
data. A message segment of the Standard toolbar helps guide you along, but
it does not accept input like the AutoCAD command line does. You’ll also find
that the status bar located in the lower left corner of the screen often contains
pertinent information.
B
What is a panel bar?
Imagine if AutoCAD were smart enough to display the appropriate toolbar,
depending on where you were in your design process. If you were dimension-
ing, the Dimensioning toolbar would automatically appear. If you were editing
your drawing, the Modify toolbar would appear, and so forth. Well, Autodesk

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Inventor is smart enough to supply you with the tools appropriate for the
particular mode you are in. On the left side of the screen (by default), you’ll
find the panel bar acts much like an intelligent toolbar. If you are sketching in
2D, the panel bar displays the 2D tools. When you are ready to turn your 2D
sketch into a 3D feature, the panel bar switches to display your 3D tools. You
spend less time looking for commands and more time focusing on the design.
How do I use the Autodesk Inventor browser?
In the lower left corner of the screen, a browser panel displays a history of
how your geometry was created. As you select the items in the browser, you’ll
find that the designated geometry highlights on the screen. It’s easy to edit
your file by selecting the desired geometry from the browser. In AutoCAD we
select our geometry by using the Crossing and Standard Window selections
(which, incidentally, also works in Autodesk Inventor). You’ll find that the
browser is a nice addition for selecting those hard-to-reach parts.
What happened to my UCSICON?
The UCSICON has been replaced with a color-coded 3D indicator. The red
arrow indicates the X direction, green indicates the Y direction, and blue
indicates the Z. We’re extremely dependent on the UCSICON in 3D AutoCAD,
but in Autodesk Inventor I think you’ll find your reliance on the 3D indicator
is minimal.
You can turn on a variety of snap and grid settings as well as an origin point
if that makes you feel more comfortable. In fact, if you insist on using coordi-
nates while drawing, you can turn on Precise Input (but I’ll try to talk you out
of that).
Take a spin through this simple and logical user interface—it won’t take long
for you to feel right at home in the Autodesk Inventor environment.

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3
Learn to Love Autodesk
Inventor File Types
A
B
In the world of AutoCAD software, we spend most of our time dealing with
just one file type—DWG. Paper space, model space, 2D, and 3D all exist
in the same file. The Autodesk Inventor world is quite different in this
respect—you’ll be dealing with a minimum of four different file types on a
regular basis. Your first response to that statement is probably not a good
one. How will you keep track of them all?
The good news is that you don’t need to—Autodesk Inventor is so smart it
does all the work for you. And since these files are all associative, any change
you make to one affects all of them. So if you choose to change a component
while in an assembly file, the software automatically updates the part file as
well as the 2D drawing file. Try not to equate this flexibility to the sometimes
frustrating external references in the AutoCAD world—this is a much more
sophisticated (and reliable) system. And I’ll do my best to help you feel com-
fortable with each of those four file types by the time you finish Step 3!
A
IPT—Inventor Part File
I tend to equate the Autodesk Inventor IPT file to AutoCAD model space.
Here you’ll create one 2D or 3D part at a scale of 1 to 1. If you choose to create
a sheet metal file, you’ll also notice the extension is that of an IPT file.
Incidentally, Autodesk Inventor has some fantastic tools for creating sheet
metal parts and flat patterns! I typically begin drawing in the IPT file.

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C
D
B
IAM—Inventor Assembly Model
When you’re ready to put multiple parts together into a final assembly you’ll
create an IAM file. Here you might find a mixture of parts, subassemblies, and
assemblies. You can also, however, create part files in the IAM environment.
Each part you create is saved to an IPT file.
C
IDW—Inventor Drawing File
If the IPT file is equivalent to model space, then the IDW is equivalent to an
AutoCAD layout (or paper space). Here you create your final drawing file for
output. An IDW file can contain views of parts, assemblies, or presentation
files, or all three. It’s also super easy to create section views, detail views, and
projected views (all of which can be painful in AutoCAD). You’ll also find that
dimensions and balloons are practically automatic in the IDW.
D
IPN—Inventor Presentation File
There’s no better way to effectively communicate how parts are assembled or
disassembled than in a presentation file. Anyone who has had to write up
pages and pages of assembly instructions can appreciate that a picture is
worth a thousand words (sometimes literally!). The IPN file is used to effective-
ly display an exploded assembly. By tweaking the various components of the
assembly, you can easily create a simple animation that’s saved as an AVI file.
Remember that all these files are associated. So if you change a part in an
assembly file, Autodesk Inventor automatically knows to apply the update in
the part, drawing, and presentation files, thus ensuring that all your files are
up-to-date. And it does this without additional input from you!

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4
Build a Part:
Start with a Sketch
A
B
We’ve got some of the basics down—so now where do we begin?
The process for building parts with Autodesk Inventor is simple:
• Select a plane to sketch on
• Make a sketch
• Constrain the sketch
• Dimension the sketch
• Conver t the 2D sketch into a 3D part
That’s it. And, believe me, it’s just as easy as it sounds.
A
Getting Started
It all starts with a simple sketch, just like you’ve been drawing on a napkin all
these years. All sketches must be drawn on a sketch plane (makes sense), and
when you start a new part file a sketch plane is automatically set up for you.
The next step is determining the shape for your base sketch. Take a look at
the part you want to create and determine the shape that best resembles the
overall part. Try to start with a flat face, since they’re much easier to work with.
After determining your base sketch, you’re ready to begin drawing.
B
Sketching Made Simple
There are so many great sketching features in Autodesk Inventor there is no
way I could possibly cover them all in this booklet—so I’m just going to high-
light a few key aspects of the part-building process.

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