Avatech Tricks: Speed Up Projected View Creation9 Jun, 2006 By: Joe Bartels
Take advantage of AutoCAD Mechanical's built-in construction features and speed up projected view creation.
Projected view creation in AutoCAD can be a tedious process. Traditionally, projected views were created using a combination of object snaps and object tracking with geometry created and then deleted.
AutoCAD Mechanical has many powerful tools that often are underused, such as the construction tools. For this article. I'll show you how to save time by using construction tools to create a view. I'll use a sample bracket drawing that contains the front and top views already finished (figure 1). The right view needs to be finished.
Figure 1. As an example, let's start with a sample bracket drawing that has front and top views.
To set up crosshairs that will project construction lines from one orthographic view to another, turn on construction line projection by choosing the Design pull-down menu, then the Construction Lines and select Projection On/Off (figure 2).
Figure 2. To turn on construction line projection, go to Design/Construction Lines and turn Projection on.
Press Enter to accept the On option in the command line. Select a position for the crosshair origin between the two views and to the right as seen in figure 3. To finish off the command, select the top right quadrant of the crosshair to set the symmetry line. If set correctly, the crosshairs should match figure 3.
Figure 3. Position the crosshair between the two views and to the right.
It's now time to start placing construction geometry. To align the right view correctly, draw some horizontal construction lines from the top view to project to the right. To access all of the construction geometry tools go to the Design pull-down menu, then the Construction Lines menu and select Draw Construction Lines (figure 4).
Figure 4. Go to Design/Construction Lines and select Draw Construction Lines to access tools.
A form appears showing you all of the different types of construction geometry tools. For this example, select the horizontal construction line tool (figure 5). In the graphics window, selected the key points from the top view using object snaps to create horizontal lines (figure 6). Notice that the construction lines are projected to the right view. With projection on, all horizontal construction lines placed in the top view are projected 90 degrees along the symmetry line.
Figure 5. Select the construction line tool.
Figure 6. Next, select the key points from the top view using object snaps to create horizontal lines.
Instead of placing individual horizontal construction lines in the front view, next use the Automatic Construction Lines tool to create the construction lines in one step. Access the tool by going to the Design pull-down menu, then the Construction Lines menu and select Automatic Construction Lines (figure 7).
Figure 7. Go to Design/Construction Lines to select the Automatic Construction Lines tool.
The Automatic C-Line Creation dialog box appears. For this example, make the lines to go the right as shown in figure 8. Pick objects to finish off the command. This example shows a crossing window (figure 9), but any method of selecting objects works.
Figure 8. Draw the lines to the right.
Figure 9. Here I used a crossing window to select objects, but any method works.
With all of the construction geometry placed between the top and front views, it's easy to place the geometry for the right view. With the object snaps set to intersection, let's drop in the geometry to the intersection of the construction lines (figure 10). Here, I also use the power view and construction geometry to create the right view of the holes and slots.
Figure 10. Set object snaps to intersection and drop in the geometry.
Once the geometry is created the construction geometry has no use. If you need to use the geometry again, turn off the construction line layer by typing Amclineo at the command line. To erase all construction lines, type in Ameraseallcl from the command line.
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