Graphics Programs Reference
In-Depth Information
5. At the Select solid to keep or [keep Both sides] <Both>: prompt, click the part
of the box that is below the surface. The top part of the box disappears, and you see the
surface once again.
6. Delete the contour surface and the contour lines. The box remains with an imprint of the
surface, as shown in Figure 20.56.
FIGURE 20.56
The box with the
contour surface
imprinted
In step 3, you saw a prompt that offered a variety of methods for slicing the box. The Surface
option allowed you to slice the box using an irregular shape, but most of the other options let
you slice a solid by defi ning a plane or a series of planar objects.
Finding the Volume of a Cut
A question I hear frequently from civil engineers is, How can I i nd the volume of earth from an
excavated area? This is often referred to as a cut from a cut and fi ll operation. To do this, you fi rst
have to create the cut shape. Next, you use the Interfere command to fi nd the intersection between
the cut shape and the contour surface. You can then fi nd the volume of the cut shape using one of
AutoCAD's inquiry commands. The following exercise demonstrates how this is done.
Suppose that the contour model you've just created represents a site where you'll excavate a
rectangular area for a structure. You want to fi nd the amount of earth involved in the excava-
tion. A rectangle has been placed in the contour drawing representing such an area:
1. Select Wireframe from the Visual Styles menu on the Viewport Controls. This allows you
to see the excavation rectangle more clearly.
2. Click the Extrude tool in the Tool Sets palette.
3. Select the rectangle shown in Figure 20.57. If the rectangle is not highlighted, press
A-spacebar until it is.
4. Click to select the rectangle and press ↵.
5. Extrude the rectangle to the height of 10´.
Search WWH ::




Custom Search