In our case, the profile consists of various teeth. Begin by drawing one of
these teeth, which will be copied later to obtain the entire profile.
Creating a size-55 auxiliary line
|
-
Choose the Line option, by going to Geometry
Create
Straight
line or by going to the GiD Toolbox.
Footnote: The GiD Toolbox is a window containing the icons for the
most frequently executed operations. For information on a particular tool,
click on the corresponding icon with the right mouse button.
-
Enter the coordinates of the beginning and end points of the auxiliary line.
For our example, the coordinates are (0, 0) and (55, 0), respectively. Besides
creating a straight line, this operation implies creating the end points of the
line.
Footnote: The coordinates of a point may be entered on the command
line either with a space or a comma between them. If the Z coordinate is not
entered, it is considered 0 by default. After entering the numbers, press Return
. Another option for entering a point is using the Coordinates Window ,
found in Utilities
Tools
Coordinates
Window .
-
Press ESC to indicate that the process of creating the line is finished.
Footnote: Pressing the ESC key is equivalent to pressing
the center mouse button.
-
If the entire line does not appear on the screen, use the Zoom Frame option,which
is located in the GiD Toolbox and in Zoom in the mouse menu.
Figure 2. Creating
a straight line
|
|
NOTE : The Undo
option, located in Utilities
Undo
, enables you to undo the most recent operations. When this option is selected,
a window appears in which all the operations to be undone can be selected.
Dividing the auxiliary line near "point" (coordinates (40, 0) )
|
-
Choose Geometry
Edit
Divide
Lines
NearPoint.
This option will divide the line at the point ("element") on the line
closest to the coordinates entered.
-
Enter the coordinates of the point that will divide the line. In this example,
the coordinates are (40, 0). On dividing the line, a new point (entity) has
been created.
-
Select the line that is to be divided by clicking on it.
-
Press ESC to indicate that the process of dividing the line is finished.
Figure 3. Division
of the straight line near "point" (coordinates) (40, 0)
|
|
Creating a 3.8-radius circle around point (40, 0)
|
-
Choose the option Geometry
Create
Object
Circle
.
-
The center of the circle (40, 0) is a point that already exists. To select it,
go to Contextual
Join Ctrl-a in
the mouse menu (right-click). The pointer will become a square, which means
that you may click an existing point.
-
The Enter Normal window appears. Set the normal as Positive Z and press OK
.
-
Enter the radius of the circle. The radius is 3.8. Two circumferences are
visualized; the inner circumference represents the surface of the circle.
Footnote: In GiD the decimals are entered with a point, not a
comma.
-
Press ESC to indicate that the process of creating the circle is
finished.
Figure 4. Creating
a circle around a point (40, 0)
|
|
Rotating the circle -3 degrees around a point
|
-
Use the Move window, which is located in Utilities
Move
.
-
Within the Move menu and from among the Transformation possibilities,
select Rotation . The type of entity to receive the rotation is a
surface, so from the EntitiesType menu, choose Surfaces .
-
Enter -3 in the Angle box and check the Two dimensions box.
(Provided we define positive rotation in the mathematical sense, which is
counter-clockwise, -3 degrees equates to a clockwise rotation of 3 degrees.)
-
Enter the point (0, 0, 0) under First Point . This is the point that
defines the center of rotation.
-
Click Select to select the surface that is to rotate, which in this case
is that of the circle.
-
Press ESC (or Finish in the Move window ) to indicate that
the selection of surfaces to rotate has been made, thus executing the rotation.
|
Figure 5. The Move
window
|
|
|
Rotating the circle 36 degrees around a point and copying it.
|
-
Use the Copy window, located in Utilities
Copy
.
-
Repeat the rotation process explained in section 2.4, but this time with an
angle of 36 degrees (see Figure 6).
|
Figure 6. Result
of the rotations
|
|
|
NOTE : The Move and Copy operations differ only in that Copy
creates new entities while Move displaces entities.
Rotating and copying the auxiliary lines
|
-
Use the Copy window, located in Utilities
Copy
(see Figure 9).
-
Repeat the rotating and copying process from section 2.5 for the two auxiliary
lines. Select the option Lines from the Entities type menuand
enter an angle of 36 degrees.
-
Select the lines to copy and rotate. Do this by clicking Select in the Copy
window.
-
Press ESC to indicate that the process of selecting lines is finished,
thus executing the task (see Figure 7).
Figure 7. Result
of copying and rotating the line.
|
|
-
Rotate the line segment that goes from the origin to point (40, 0) by 33
degrees and copy it (see Figure 8).
Figure 8. Result
of the rotations and copies
|
|
|
Figure 9. The Copy
window
|
|
NOTE : In the Copy and Move windows, the option Pick
may be used to select existing points with the mouse.
|
-
Choose the option Geometry
Edit
Intersection Line-line.
-
Select the upper circle resulting from the 36-degree rotation executed in
section 2.5.
-
Select the line resulting from the 33-degree rotation executed in section 2.6
(see Figure 10).
-
Press ESC to conclude the intersection of lines.
-
Create a line between point (55, 0) and the point generated by the
intersection. To select the points, use the option Join Ctrl-a in the Contextual
menu.
-
Choose the option Geometry
Edit
Intersection Line-line in order
to make another intersection between the lower circle and the line segment
between point (40, 0) and point (55, 0) (see Figure 11).
-
Then continue selecting to make an intersection between the upper circle and
the farthest segment of the line that was rotated 36 degrees (see Figure 12).
|
Figure 10. The two
lines selected
|
|
Figure 11.
Intersecting lines
|
|
Figure 12.
Intersecting lines
|
|
|
Creating an arc tangential to two lines
|
-
Choose Geometry
Create
Arc
Fillet
curves .
-
Enter a radius of 1.35 inside the command line (see footnote 2 on page 4).
-
Now select the two line segments shown in Figure 13. Then press ESC to
indicate that the process of creating the arcs is finished.
Figure 13. The
line segments to be selected
|
|
Translating the definitive lines to the "profile" layer
|
-
Select the "profile" layer in the Layers window. The auxiliary lines
will be eliminated and the "profile" layer will contain only the definitive
lines.
-
In the Sent To menu of the Layers window, choose Lines in
order to select the lines to be translated. Select only the lines that form the
profile (Figure 14). To conclude the selection process, press the ESC key
or click Finish in the Layers window.
Figure 14. Lines
to be selected
|
|
-
Click Off the profile layer.
-
Choose Geometry
Delete
All
Types (or use the GiD Toolbox).
-
Select all the lines and surfaces that appear on the screen. (The
click-and-drag technique may be used to make the selection.)
-
Press ESC to conclude the selection of elements to delete.
-
Select the "aux" layer in the Layers window and click Delete .
-
Select the “profile” layer.
NOTE: When a layer is clicked Off , GiD reminds you of this.
From this moment on, whatever is drawn does not appear on the screen since it
is in the hidden layer.
NOTE: To cancel the deletion of elements after they have been selected,
open the mouse menu, go to Contextual and choose Clear Selection .
NOTE: Elements forming part of higher level entities may not be
deleted. For example, a point that defines a line may not be deleted.
NOTE: A layer containing information may not be deleted. First the
contents must be deleted.
Rotating and obtaining the final profile
|
-
Make sure that the activated layer is the "profile" layer. (Use the option Layer
To use. )
-
In the Copy window, select the line rotation (Rotation , Lines
).
-
Enter an angle of 36 degrees. Make sure that the center is point (0, 0, 0) and
that you are working in two dimensions.
-
In the Multiple Copies box enter 9. This way, 9 copies will be made,
thus obtaining the 10 teeth that form the profile of the model (9 copies and
the original).
-
Click Select and select the profile. Press the ESC key or click Finish
in the Copy window in order to conclude the operation. The result is
shown in Figure 15.
|
Figure 15. The
part resulting from this process
|
|
|
-
Create a NURBS surface. To do this, select the option Geometry
Create
NURBS
Surface
By Contour. This option
can also be found in the GiD Toolbox.
-
Select the lines that define the profile of the part and press ESC to
create the surface.
-
Press ESC again to exit the function. The result is shown in Figure 16.
Figure 16.
Creating a surface starting from the contour
|
|
NOTE : To create a surface there must be a set of lines that define a
closed contour.