Wiley 978-1-1180-1681-7 Datasheet download pdf (Page 28)

CHAPTER 1 The Basics of auTocaD civil 3D

cr e a t e mu l t i P l e cu r v e s co m m a n d

The Create Multiple Curves command lets you create several curves that are tangentially con-

nected. The resulting curves have an effect similar to an alignment spiral section. This command

can be useful when you are re-creating railway track geometry based on ﬁeld survey data.

The command prompts you for the two tangents. Then, the command line prompts you as

follows:

Enter Number of Curves:

The command allows for up to 10 curves between tangents.

One of your curves must have a ﬂexible length that’s determined on the basis of the lengths,

radii, and geometric constraints of the other curves. Curves are counted clockwise, so enter the

number of your ﬂexible curve:

Enter Floating Curve #:

Enter the length and radii for all your curves:

Enter curve 1 Radius:

Enter curve 1 Length:

The ﬂoating curve number will prompt you for a radius but not a length.

As with all other curve commands, the speciﬁed geometry must be possible. If the command

can’t ﬁnd a solution on the basis of your length and radius inputs, it returns no solution (see

Figure 1.34).

Figure 1.33

The ﬁrst image

shows two lines

with a desired

pass-through

point. In the

second image,

the Create Curve

Through Point

command draws a

curve that is tan-

gent to both lines

and passes through

the chosen point.

Figure 1.34

Two curves were

speciﬁed with the

#2 curve desig-

nated as the ﬂoat-

ing curve.

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Wiley 978-1-1180-1681-7 Datasheet Page 28