AutoCAD Civil 3D

[#1]

hi
im new in civil 3d.. how i can add a spiral curve spiral to two entities(not only alignments) ? would u please tell me the commands step by step?
thank u Edited by: atusa60 on Jul 31, 2009 4:32 AM

[#2]

You can only add these between alignment segments. You could temporarily
make an alignment, create the spiral and explode.

Curious, why woould you need a spiral that's not part of an alignmnet?

Matt

[#3]

Hi atusa60,

You can't draw an accurate spiral with AutoCAD, only multiple arc
polyline approximation.

Hence, if you want accurate spiral information and drafting, you have no
option but to use an alignment.

If you can accept the approximation, Mark has told you how to do it.

Regards,


Laurie Comerford


atusa60 wrote:
> hi
> im new in civil 3d.. how i can add a spiral curve spiral to two entities(not only alignments) ? would u please tell me the commands step by step?
> thank u
>
> Edited by: atusa60 on Jul 31, 2009 4:32 AM

[#4]

Who's Mark?

[#5]

Hi Matt,


Oops! Sorry Matt. I didn't have my glasses on and misread your name.

Regards,


Laurie Comerford


Matt Kolberg wrote:
> Who's Mark?

[#6]

I have to enter deed information and some times along highways and railroads the boundary is a spiral curve. In LDD 2004 this was a command with in the lines and curves menu.

[#7]

Any ideas of how to fake it in from just a back tangent, a delta, a length and whatever A=1/2 means? I dont have a PI or anything to tie in the begin curve so I need to figure the end of the spiral some how. Anybody?

[#8]

"A" equals the deflection angle off tangent from TS to SC. FYI

[#9]

Are you sure that the spirals you're entering are clothoid type?  Civil3d only uses clothoid but many old railway and highway designs used other spiral definitions.

[#10]

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SBoon wrote:

Are you sure that the spirals you're entering are clothoid type?  Civil3d only uses clothoid but many old railway and highway designs used other spiral definitions.

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I'm pretty sure Civil 3D can use other types of spirals. If you go into the "Curve and Spiral Settings" on the create alignments toolbar, there is an option to change the spiral type (at least I'm pretty sure that's what that setting is for, unless there are other types of curves).