Civil 3D corridors have been able to seek out multiple targets for several releases now. However, It has been my experience that it often chose unwisely. The classic example is an intersection where I wanted the same corridor region to target the centerline of one road and the edge of another. More often than not it would get the horizontal target right but not the vertical, resulting in a pretty rough looking intersection. This would lead to more work forcing me to create two distinct regions with single targets so that Civil 3D could get it right. Of course the new intersection tools take care of all this and more in the 2010 release but that is made possible in part by some improvements to targeting. Find out how after the jump.
When you assign multiple targets in a corridor, you now have different options as to how Civil 3D chooses between them.
For Width/Offset targets you now have two options:
The difference from 2009 is that you had only one choice which was to use the nearest offset. This usually worked out fine.
For Slope/Elevation targets you now have four options:
In 2009 there was again, only one choice which was to use the flattest slope. For any given design, that may or may not have been the best choice…in my experience it usually wasn’t. In 2010 you’ll find yourself using the Nearest Offset option more than anything which will work much better than the old way. And on top of that, you now have four choices giving you more control over how Civil 3D interprets the targets.