There is an update available for AutoCAD Civil 3D 2010 from Autodesk AutoCAD Civil 3D & AutoCAD Civil Services & Support.
This update and Hotfix is for users who installed AutoCAD Civil 3D 2010 Update 2 and then open a previous version of Civil 3D which contains an alignment with a spiral curve.
The Hotfix corrects the alignment geometry where as before installing the Hotfix you may have seen a change in the alignment upon opening your AutoCAD Civil 3D 2010 drawing.
Take note of the following because there are two separate Hotfixes depending on the status of your updates and if you have the Subscription Advantage Pack installed:
Note: There are two different hotfixes for this issue. One is for users who have only Update 2 installed. The other is for users who have both Update 2 AND the Subscription Advantage Pack installed. If you are unsure which is appropriate for your application, please follow the instructions below to find out:
Professional Land Surveyor Source – Autodesk
Prior Version Alignment Spiral Hotfix
Applies to: AutoCAD® Civil 3D® 2010
Follow this link to the Autodesk AutoCAD Civil 3D & AutoCAD Civil Services & Support to get the most up to date information and to download the Hotfix.