3D Length of Feature Line vs. Exploded Alignment (Polyline) - What's the differe

[Anonymous]

Hello everyone!

I am sort of new to this community and software (Civil 3D 2018 on Windows 10) but I've been googling around alot and I do really enjoy finding solutions on the forum!

Sadly I've encountered a problem which I can't get my head around:
I want to measure an alignment (the 3D length) and first I used to explode the alignment in the profile view and turn it into a polyline to get the length of it. Then I found feature lines (great?!) but to my surprise the length do not correspond to the length of the polyline from the explode profile line. What is the difference between them? My feature line seems to follow the profile very much but still there's less than 2 m differences between the alignment (which is not based on the profile, or?) and the feature line (which is over 3000 m in the plane), which follows the alignment.

So the TL;DR:

Why do not the 3D Length of a feature line correspond with a polyline from an exploded profile from a profile view?

I attached a picture to maybe make it easier for readers to understand the situation.

Thanks in advance for any kind of help!
Best regards,

Fredrik

[tcorey · Accepted solution]

Have you taken into account the fact that the profile view might have exaggerated vertical scale?

[Anonymous]

No I hadn't! Thanks! Still surprised the difference is so small between the alignment and feature line since the elevation along the alignment varies almost +- 20 m! I think I have to cut up the profile and compare to straight lines!

Once again, thanks! Super fast answer as well! 🙂