CREATING THE AUXILIARY LINES
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The auxiliary lines used in this project are those that make it possible to
determine the center of rotation and the tangential center, which will be used
later to create the model.
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Choose the Line option, by selecting Geometry
Create
Straight
line .
Footnote: This option can also be found in the GiD Toolbox.
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Enter the coordinate (0, 0) in the command line.
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Enter the coordinate (200, 0) in the command line.
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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.
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If the entire line does not appear on the screen, use the option Zoom Frame,
which is located in the GiD Toolbox and in Zoom in the mouse menu.
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Again, choose Line . Draw a line between points (0, 25) and (200, 25).
The result is shown in Figure 2.
Figure 2
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Go to the Copy window (Figure 4), which is found in UtilitiesCopy
.
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Choose Rotation from the Transformation menu and Lines from
the Entities Type menu.
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Enter an angle of -60 degrees and click on Two dimensions .
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Enter point (200, 0, 0) in First Point . This is the point that defines
the center of rotation.
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Click Select to select the first line we drawn.
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After making the selection, press ESC (or Finish in the Copy
window) to indicate that the selection of lines to be rotated is finished. The
result is shown in Figure 3.
Figure 3. Creating
the axes
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Figure 4. The Copy
window
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Creating the tangential center
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Choose the menu option Geometry
Create
Straight
line. On the mouse menu, choose Contextual and use Join Ctrl-a
to select points (0, 0) and (0, 25). Press ESC.
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In the Copy window, choose Rotation from the Transformation
menu and Lines from the EntitiesType menu. Enter an angle of 120
degrees, and the coordinates (0, 25, 0) in First point also check the Two
dimensions option. Finally select last line created.
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In the Copy window, choose Translation from the Transformation
menu and Lines from the EntitiesType menu. The translation vector
for the translation to be made is the line just created. As the first point of
the translation, select the point farthest from this line segment. For the
second point, select the other point of the line (Figure 5). To select an
existing point, you must change the “No Join / Join” option located in the
contextual submenu from 3rd mouse’s button menu or use the shortcut
(Control-a), notice that the cursor change from a cross to a box.
Figure 5. The line
segment selected is the translation vector.
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Figure 6. Result of
the translation with copy
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Click Select to select the line segment that forms an angle of -60
degrees with the horizontal. Press ESC to indicate that the selection
has been made.
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Choose Geometry
Edit
Intersection
Line-line
.
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Select the two inner lines.
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Click Yes to confirm that there is an intersection and that, therefore,
the shortest distance between the two entities is 0. The intersection between
the two entities (lines) creates a point. This point will be the tangential
center.
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Press ESC to indicate that the process of intersection between lines is
finished.
Figure 7. The
auxiliary lines with tangencia center
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NOTE : The Undo option allows you to undo the operations most
recently carried out. If an error is made, go to Utilities
Undo
; a window appears where you can select all the options to be eliminated.