Topic: Can Volumes Be Trusted?

[dfarris75]

Has anyone done any extensive testing on Civil 3d's volume calcs? I am wondering how much everyone trusts the program to do the calcs accurately. Is it just a matter of how accurate you build your surfaces? Is it trustable beyond that?

[mjfarrell]

and what has led you you to this question?

[dfarris75]

It's really just a general question, but particularly posed by one of our engineers. I had brought this up with you before several months ago when said engineer was doing some basic testing and the volumes were incorrect as I recall.

Just wanted some opinions from everyone, mostly from those who utilize this aspect of the program more than we do.

[sinc]

What exactly does "the volumes were incorrect" mean?

I've never seen C3D fail to perform a solid calculation, based on the surfaces provided.  However, I have seen people try to use garbage surfaces, and I have also seen people get confused by how boundaries work.

[dfarris75]

In all honesty I don't remember for a fact that he or I performed a test that gave incorrect numbers, but I'm just referring to the numbers that it gives. Is the software pretty good about giving you accurate numbers so long as your surfaces are correctly built?

It has always been a question that engineers here ask me. I've had some engineers flat out tell me that they simply don't trust the software. Not sure if they are just distrustful of the software writers or if they have worked with cadd guys in the past that gave them screwy numbers on a faulty model.

[sinc]

So if I understand you correctly, you're saying that there's a rumor floating around your office that C3D is untrustworthy on volume calcs, and everyone is latching onto that as a reason to avoid learning C3D?

[mjfarrell]

I think they need to learn the software, then test the results.
And how and what one uses for various 'volume' calculations is important.
Too often I see files with way too many surfaces, with funky names, and no descriptions, it's no wonder there is a question about the data.

[dfarris75]

So if I understand you correctly, you're saying that there's a rumor floating around your office that C3D is untrustworthy on volume calcs, and everyone is latching onto that as a reason to avoid learning C3D?

I don't know if I would go that far, but in my 7+ years working in the civil field this is a recurring theme among the engineers. One of them in my first couple of years here even did all of his cl geometry by turned angles because he didn't trust the program to label bearings and distances. This was very annoying and happened back when I knew very little of how to use LDD so I was unable to convert him.

Now we have Civil 3D and I've put much effort, as Mike can tell you, into learning how to use it, but I still have engineers posing these questions.

I'm coming to the realization that our company will likely never pursue full use of the software in which they have invested unless I can somehow break the barrier by doing an entire project using Civil 3D and completing in record time. This will be difficult since I still need a bit more training to get there. Or maybe I am the problem and am jutht nawt thmawt enuff.

[mjfarrell]

they wont get it until they use C3D

[sinc]

I don't know if I would go that far, but in my 7+ years working in the civil field this is a recurring theme among the engineers. One of them in my first couple of years here even did all of his cl geometry by turned angles because he didn't trust the program to label bearings and distances. This was very annoying and happened back when I knew very little of how to use LDD so I was unable to convert him.

I'm not sure what to do about that.

Personally, I don't think it's worthwhile inventing problems.  It's one thing to try to use the software, and get bitten by problems.  It's another thing to imagine possible problems, and then avoid using the software because of imagined fears.  But how to convince your staff of that?   

[dfarris75]

I dunno. I'm getting really weary of it though, especially with our light workload over the last year + which continues to diminish in the poor economy. If another opportunity opened up for me I'd likely jump on it.

[doggarncity]

I dunno. I'm getting really weary of it though, especially with our light workload over the last year + which continues to diminish in the poor economy. If another opportunity opened up for me I'd likely jump on it.

Well, my input would be that you set up a surface flat, if need be, then create a cube of sorts with a known volume on that surface. Let the software do it's thing and see if it can get a good volume as a baseline. I always had to do my volumes with the avg. end area method and that can be checked easy enough with excell spreadsheets to double check it. Once demo'd to the troops that might be a reliable way to convince the old guard that things can work. Something I learned when I did a railroad job in Alaska with with a template and surface... but just a thought. I shouldn't take to much to create a know volume surface to test and report on.

Mike

[dfarris75]

Yeah I was doodling around with some real simple surfaces like that the other day. It seemed to be working just fine.