EXERCISE 1.1 – MODELING A SHAFT
Figure 1: The shaft and its model tree.
Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Learning Targets
In this exercise you will learn:
 Making sketches and dimensions.
 Creating models in part mode and saving them.
 Using basic features to add or remove material (revolve, extrude).
 Creating datum planes.
 Using basic features to modify material (round, chamfer).
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Getting Started
Start Creo Parametric (using the shortcut created in Exercise 1.0). Select New from the Home ribbon
(Figure 2) or select File  New.
Figure 2: Selecting New from the Home ribbon.
The New window opens. Ensure that under Type Part is selected and Sub-type is Solid. Give a name to
a new part, in this case shaft (Figure 3). Notice, that Use default template is selected. That means that
new parts are created by copying one template part from Creo installation folder (defined in a setting
file config.pro). Select OK when ready.
Figure 3: Dialog box for New.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 4: New part in part mode.
As you notice in Figure 4, there are four features already in the model tree (on the left). These
features are three basic planes (RIGHT, TOP and FRONT) and one coordinate system (PRT_CSYS_DEF).
In the model tree, there is a green arrow labeled Insert Here. It means that new created features are
placed where the arrow points. You can drag the arrow and drop it to a new position in the model
tree allowing adding some features between existing features. The model tree is history based; it
means that if you are moving upwards in the model tree you are also moving back “in time” and vice
versa.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Creating the first feature
Defining the feature
Our plan is to design a shaft. A shaft is usually symmetric to its center axis, thus the best tool for
designing this kind of part is Revolve, ( ) which can be found in the Model tab (Figure 5). Select
Revolve (
) and wait for the Revolve tool dashboard to open (Figure 6).
Figure 5: Revolve tool in Model tab.
Figure 6: The Revolve tool's dashboard.
As you notice, the Placement tab is in red. It is because the tool needs a sketch. You can select an
existing sketch or create a new one. In general, if you don’t know what the tool requires, you should
check the message area in the bottom of the window (Figure 7).
Figure 7: Message area and its prompt related to Revolve tool.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Defining a sketch
Sketching procedure:
1. Selecting the sketching plane and reference plane
2. Sketching rough geometry
3. Defining geometric constrains
4. Defining dimensions
5. Giving actual dimension values
Select the Placement tab and click Define; this allows creating an internal sketch. The Sketch window
opens. First we need to select the sketching plane, so select the RIGHT plane (from graphical area or
from model tree). The program has probably selected TOP plane as a reference plane, but if not, click
the right box next to Reference and select the TOP plane. Next we need to define the orientation of
the sketch, choose Top from the drop-down menu (Figure 8). This means, that the positive side of the
TOP plane will be pointed up (positive plane side is in blue, negative in red). If your Sketch window
values look like in Figure 8, click Sketch.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 8: Sketch-window and its values. Selecting Orientation for sketch. Sketching plane highlighted in green,
reference plane in blue.
The sketch mode opens and view is adjusted to 2D. Notice that the positive side of the TOP plane
points upwards as desired (Figure 9).
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 9: Sketch mode
First we create a centerline (from the Datum group). Click the Centerline tool ( ) and select one point
from the horizontal reference line (turquoise dashed line), then another point from the same line.
Close the tool by pressing the middle mouse button (MMB). In general in Creo, tools are active until
you close them. The just created centerline will be an axis of revolution for our revolve feature (the
sketch will be rotated over this centerline).
Now we design a profile geometry: Select Line (
, Sketching group). Start from the middle and select
points as shown in Figure 10. When the loop is completed, accept it by clicking MMB and close the
tool by pressing MMB again.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 10: Sketched lines, starting from the middle (1) until loop is closed (11).
Figure 11: Weak dimensions made by program (grey).
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
As you can see, the program has provided the dimensioning. The dimensions made by Creo (colored
in gray) are called weak dimensions. It means that the program can remove or change them when
needed. This is the reason why we do not want to see any weak dimensions; we want to have full
control over the sketch. The automatic dimensioning may look like this (Figure 11). Please note, that
the values of the dimensions can be different, in this stage we do not care about nominal values, we
only care about that the needed dimensions exist.
Before we add our own dimensions, we can remove one unnecessary dimension; in our shaft the
diameter of the shaft should be the same in both ends (length from point 1 to 2 and from 9 to 10
should be the same (in Figure 10)). To tell that two lines have equal length, choose Equal ( ) from
Constraint group and select two lines (from 1 to 2 and from 10 to 9) and MMB. The L1 text appears
near selected lines to mark the equality.
Figure 12: Two lines selected (green) and moment before MMB between those lines. Notice the equality of the lines
(L1)
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
In order to create our own dimensions, the Normal tool can be used (
, in the Dimensions group).
This tool can be used to create all kind of dimensions, such as the length of the line, distance between
two points/lines, radius of an arc, diameter of an arc and angle between two lines. Select the Normal
( ) tool and select lines 4-5 and 6-7 (in Figure 10) and press MMB; the new, user defined dimension
(blue) appears where the mouse was. The tool is still active. Using this tool, create needed dimensions
as seen in Figure 13. Different kind of dimensioning methods are showed in Exercise 1.0, consult it if
needed. When done, close the Normal tool by pressing MMB. To change the values of the
dimensions, just double-click dimension and give a new value as seen in Figure 13. Notice that
dimensions are now in green and locked. To move the dimension value label location, select it holding
LMB and move it to the new desired location.
Figure 13: Sketch done. Locked dimensions in green.
Next check that the sketch fulfills the requirements for Revolve feature by selecting Feature
Requirements ( ) from Inspect group in the ribbon. If everything looks ok, close the window with
Close. Now the sketch is finished. Accept the sketch with
(OK, Close group in ribbon).
Finalizing the revolve
We are back in the part mode and the preview of our defined shape appears. The view is normal to
sketching plane. To reorient the part, hold MMB to rotate the view (Figure 14). By default the rotation
angle for revolve is set to 360, but it can be changed by double clicking the value in graphical area or
selecting the value field in the dashboard. The angle of 360 is fine for our shaft, so accept the Revolve
by selecting Done (
).
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 14: The preview of revolve
The revolve feature is now displayed in the model tree. Select it by pressing RMB and select Rename
from the menu. Renaming the main features of your model with meaningful names increase its
readability, helping other users understanding your design intent. Give BASE as a name for the
feature. Notice that Creo is not case sensitive, but it will show all user changed features with
uppercase letters, even when they are defined in lowercase.
Saving the model
Save the model by selecting
from Quick Access bar or by pressing CTRL-S and selecting Save. The
saving location for your file is always the working directory or location from where your model has
been opened. Except when you are saving your model for the first time, then you can change the
saving location. It is good practice to always save your models in your working directory (which is
defined by shortcut, see Exercise 1.0) to keep control over your files.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Save the model again (
Windows Explorer (
Kaur Jaakma
2012, updated 2015
or CTRL-S and select Save or MMB). Now open your working directory using
Computer and so on… or press Windows-button on your keyboard (
)+E
and so on…). You can see that there are two files named as shaft: shaft.prt.1 and shaft.prt.2 (Figure
15). Every time you save a model, a new version of the model is created. This allows you to go back in
time and open some older version of your model. By default Creo always opens the newest version of
the file (higher number), but you can also open an older version. (When opening a file in Creo, select
Tools and All versions to see all versions of the files you have in that folder.)
Figure 15: Example of a working directory and its files. Notice two shaft.prt.# files.
In general, remember to save the model often! In the first exercises saving after each feature is highly
recommended.
Making a Keyway
We want to have a keyway in the longer end (FRONT plane side) of our shaft. To make a keyway, a
new plane parallel to TOP plane and attached to the previous feature is needed.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Creating a new plane
Select Plane ( ) from Datum group. The Datum Plane window appears. Select the TOP plane and
notice, that the plane is listed in References field. Click Offset text in References field and select
Parallel from drop-down menu (Figure 16). Then hold CTRL and select the surface (highlighted in
Figure 17). Change Through to Tangent in Reference field. The references should look like in Figure 17.
Accept the feature (OK).
Figure 16: Selecting Parallel from drop-down menu.
Figure 17: Finished Datum Plane definition. References (plane and surface) showed in green.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Now we have made a plane that is parallel to TOP plane and follows the diameter of the shaft. This
plane doesn’t have any dimensions; its location is defined by existing geometry. Click somewhere in
the background to deselect the previously created plane (plane should not be highlighted in green).
Creating a cut
To make a cut for the keyway, select Extrude ( ) from Shapes group. The Extrude tool dashboard
opens. Select Placement tab and then Define to open Sketch window. Select previously created plane
as a sketching plane and RIGHT plane as reference plane (if not automatically selected). Set
Orientation to Bottom (positive side of the plane will be pointing down) (Figure 18). Select Sketch.
Figure 18: Sketch definition for a keyway and selecting Bottom as Orientation.
Now we are in the sketch mode. Next we sketch two lines (Line ( ), Sketching group) as shown in
Figure 19. Select left plane as a starting point (1) and then some point in the right as second point (2).
Close loop with MMB, the tool is still active. Select a left plane as first point (3) and move mouse to
right until it snaps and shows a letter L over both lines and select that point (4). Click MMB twice to
close the loop and the tool. Now two equal length (L1) and horizontal (H) lines are created.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 19: Creating second line, notice snapping for equal lengths (letter L). Letter H tells that the line is horizontal.
Next we use Arc (
, 3 point arc) from Sketching group to connect previously made lines (we want to
have a U shape keyway). Select the Arc (
). Select point 2 in Figure 19 as a starting point, point 4 as
an ending point, move mouse right until arc snaps and offers tangency (letter T) (Figure 20) and select
that point. MMB to close the Arc tool.
Figure 20: Arc tool and snapping to offer a tangency constraint (T).
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
To define a keyway we need only two dimensions (width and length) but in the sketcher we have
three dimensions. Reason for this is asymmetry in the sketch. In this case, the easiest way to define
symmetry is to attach arc’s center point to horizontal reference line (RIGHT plane). This can be done
by using Coincident constraint ( , Constrain group). Select that tool, select arc’s center point and
then select horizontal reference line (Figure 21). The tool is still active, MMB to close the tool.
Figure 21: Coincident constraint, arc's center point selected and selecting the horizontal line.
Because we just created a new geometric constraint (Coincident), one Creo’s weak dimension has
been eliminated; we have two dimensions that can define the shape. We have a length dimension
(from a reference plane to arc’s center point) and a radius of an arc. Next create a new dimension by
using Normal ( , Dimension group). Select one sketched horizontal line (yellow), select other
sketched horizontal line and MMB between those lines. Give values as shown in Figure 22.
Figure 22: Finished sketch for Extrusion.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Now we have a sketch that is open and contains three objects (line, arc and line) in a chain. When
making cuts, the sketch can be an open loop, if the open points are attached to the side of the
geometry (in this case, attached to the vertical reference line). If the open points are inside the
geometry, it will not work. If sketch looks like in Figure 22, select OK ( ) from Close group or hold
RMB and select OK from the list.
Finalizing the extrusion
We are back in the part mode. In Creo, basic geometry creating tools can be used both for adding and
removing material. Therefore, select Remove Material ( ) from the dashboard to make a cut. Next
the depth and the direction of the cut is needed to be defined. Give the depth of 3. The cut direction
is by default upwards (the positive side of the sketching plane). It can be changed by clicking the
highlighted arrow in Figure 23 (or by clicking the leftmost
one
symbol in the dashboard). The rightmost
symbol changes the side of the removing area; click that a couple of times to see what it does.
When the dashboard and the model looks like in Figure 23, accept the feature ( ). Select the just
created feature from the model tree, click RMB and then Rename (or select feature and F2) and name
it as KEYWAY.
Figure 23: Final values for Extrude.
Remember to save your model!
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Creating a Groove
Next we make a cut to help positioning the wheel to our shaft. Select Revolve ( , Shapes group),
hold RMB on the graphics area and select Define internal sketch from the menu. The Sketch window
opens, select RIGHT as Sketching plane, TOP as Reference plane and Orientation as Top (if not
automatically selected). Select Sketch.
Making a sketch
Figure 24: Location for the groove.
We want to create a groove that is attached to the existing geometry (in this case BASE feature,
highlighted in Figure 24). If any changes are made in the main dimensions of the shaft, a groove
follows those changes and updates its location. In order to create sketch lines that are attached to the
existing geometry, we need to change the references. A reference can be a plane, a surface, an edge,
a point etc., basically anything where something can “snap”. In previous sketches, we used the default
references that are mostly the base planes (FRONT, RIGHT etc.), so our geometry was attached only
to those planes. Now we want that our sketch (and therefore the feature) follows the surfaces of an
existing feature.
Select References ( , Setup group) or hold RMB and select References; the References window
opens. There are two planes listed (TOP and FRONT), select them and click Delete. Then select the
two surfaces shown in Figure 25. Notice turquoise dashed lines; one horizontal, other vertical.
References doesn’t have to be vertical or horizontal, they can be pointing anywhere. Close the
References window by selecting Close.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 25: References for the groove.
Select under Arc ( ) Center and Ends ( ) as seen in Figure 26. Then select arc’s center point (1) on the
horizontal reference line, the starting point (2) on the crossroads of the two reference lines and the
endpoint (3) on the horizontal reference line (Figure 26). Click on MMB to close the arc tool.
Figure 26: On the left: selecting Center and Ends. On the right: creating an arc.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
For this sketch, only one dimension is automatically created and it is a radius dimension. In this case,
using the radius dimension does not reflect the desired design intent. Thus, we need to create a new
dimension: Select Normal ( , Dimension group), select point 3 in Figure 26, then point 2 and MMB to
make a dimension. Give a value of 4 and click MMB to close the tool. Now our sketch is ready (Figure
27). Notice, that we didn’t make a centerline (the axis of revolution). Accept the sketch ( or RMB
and select OK).
Figure 27: Sketch ready to accept.
Finalizing the groove
We are back in the part mode. The tool is asking us (on the bottom line of the program window:
“Select a Straight Curve or a edge, axis, or axis of coordinate system to specify axis of revolution.”) Set
Axis Display on (
) and the Plane Display off (
) from the toolbox in the top of the graphical area.
Now we can select axes from our previous features, in this case there is only one axis. Select it; this
axis is from the first revolve feature (BASE). Click Remove Material ( ) from the dashboard or hold
RMB and select Remove Material. Select Properties tab and name this feature as GROOVE. If your
screen looks like in Figure 28, accept the feature by selecting
off (
or press MMB. Set the Axis Display
).
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 28: Ready to accept Revolve.
Remember to save your model!
Rounds and Chamfers
The basic (functional) geometry of the shaft is now ready and there is only some fine tuning to do.
Last features to add are rounds and chamfers.
Creating rounds
Select Round ( ) from Engineering group. In general, tools that add or remove material are located
in the Shapes group and tools that edit material are located in the Engineering group. Select the first
edge (1), hold CTRL and select the second edge (2) as shown in Figure 29. Open the Sets tab and
notice that there is one set (Set 1) that has two edges in its References field. Change the radius value
to 2 (Figure 30) and accept the feature (
or MMB).
Figure 29: Edges for Round.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 30: Ready to accept Round.
Creating chamfers
Select Chamfer ( ) from Engineering group. Select five edges (remember to hold CTRL after the first
edge) as shown in Figure 31. Then change the dimensioning from D x D to 45 x D and give a value of 2
(Figure 32). Accept the feature (
or MMB).
Figure 31: Edges for Chamfer.
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Kon-41.3006 Computer Aided Design Basic Course
Exercise 1.1
Kaur Jaakma
2012, updated 2015
Figure 32: Changing dimensioning schema to 45 x D.
Ending Notes
Now your model should look like in Figure 1. To make your model look like in that figure, select
Shading With Reflections as Display Style (Figure 33).Notice that there are also other shading modes
to use.
Figure 33: Changing Display Style to Shading With Reflections.
We have created a shaft that is defined using the main design dimensions; diameter of the shaft,
diameter of the attaching cylinder, length of the shaft, length of the attaching cylinder etc. The
keyway and the groove are attached to BASE geometry and its main dimensions, allowing them to
follow the changes made to the main geometry. This allows other persons to use your model and
helps you to redefine your model in the future when design criteria changes.
This concludes our exercise. Remember to save your model!
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