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
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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)
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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)
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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.
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Figure 5. The Move window
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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).
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Figure 6. Result of the rotations
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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.
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- 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
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Figure 9. The Copy window
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NOTE
: In the Copy
and Move
windows, the option Pick
may be used to select existing points with the mouse.
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- 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).
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Figure 10. The two lines selected
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Figure 11. Intersecting lines
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Figure 12. Intersecting lines
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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
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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
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- 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.
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Figure 15. The part resulting from this process
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- 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
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NOTE
: To create a surface there must be a set of lines that define a closed contour.