Author Topic: Contour Battles  (Read 6090 times)

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surveyor_randy

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Contour Battles
« on: June 11, 2009, 01:13:03 PM »
Just thought I'd share something with you guys.  And I won't win the debate here in this company.  The head of our survey department is a DIEHARD terramodel user and even though we have all decided to switch to Civil 3D, he still wants to generate contours in Terramodel and uses it as the benchmark for correct contouring.  If C3D generates a contour slightly off from the one that Terramodel generates, the C3D contour is considered wrong.

When we are taking shots every 50', I tried to explain to him that true contours will not be smooth with that sparse of a grid.  So he is having everyone take an extra step of generating contours in Terramodel and them importing them into C3D as elevated polylines which are then used to build a surface.  So, IMO, we are ending up with an inaccurate surface from which to design from.  He says that this survey department will not put out 'jagged' contours in a drawing.

Is there anything I can do in Civil 3D to make the contours appear smoother to appease him?  I imagine adding a whole boatload of interpolated points to the surface might smooth them out.  But to be honest, I cannot stand working in Terramodel and I strongly believe that Terramodel is generating bogus contours on sparse data.  But I won't win this debate since I'm not the boss.

Thoughts, opinions?

Jeff_M

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Re: Contour Battles
« Reply #1 on: June 11, 2009, 02:06:50 PM »
Have you tried any of the surface smoothing methods under Surface Edits?

http://www.civil3d.com/2007/01/surface-smoothing-simplified/

surveyor_randy

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Re: Contour Battles
« Reply #2 on: June 11, 2009, 02:40:24 PM »
Yep...  I saw those a few years back.  I will have to revisit the idea.  The argument that I get is that it is "just another step" whereas Terramodel will do it right (in their opinion) the first time.

I'm actually playing with the idea of having a true C3D generated surface, turn the contours off, and then just overlay the terramodel contours for the "visual appeal"....  at least the engineers will be getting an accurate surface and not something that has been toyed with to make it pretty to the eye.

mjfarrell

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Re: Contour Battles
« Reply #3 on: June 11, 2009, 03:18:02 PM »
I think that you need to experiment with your surface style(s) and the contour smoothing functions.
You might be surprised to discover that the C3D surface and contours can vary widely depending on these settings.

And or it's time to bring me down there to Reeducate that person. (and all others that will be using C3D)
Be your Best


Michael Farrell
http://primeservicesglobal.com/

Willie

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Re: Contour Battles
« Reply #4 on: June 11, 2009, 06:11:45 PM »
Maybe a bit of topic, but still relevant. 

The previous firm I work also used two software packages.  One to create designs and Autocad to create drawings.  It sucks working with more that one software package to create a design, or in your case, contours.  If you export, you loose all the object intelligence and end up with line, polylines and text etc.  And you waste a lot of time doing cosmetic editing on drawings.

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mjfarrell

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Re: Contour Battles
« Reply #5 on: June 11, 2009, 07:57:55 PM »
Maybe a bit of topic, but still relevant. 

The previous firm I work also used two software packages.  One to create designs and Autocad to create drawings.  It sucks working with more that one software package to create a design, or in your case, contours.  If you export, you loose all the object intelligence and end up with line, polylines and text etc.  And you waste a lot of time doing cosmetic editing on drawings.



Not to mention that in the translation process there is always the potential of introducing errors.  And no matter how good you think you are if there is a potential to introduce an error it WILL happen. Ask NASA about the multibillion dollar satellite they lost due to a process that had the potential for error. (converting from Metric, to Imperial and forgetting to convert back)

I truly believe that with training that this individual would gain greater confidence in the power (accuracy) of C3D and would embrace it's use.
Be your Best


Michael Farrell
http://primeservicesglobal.com/

surveyor_randy

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Re: Contour Battles
« Reply #6 on: June 11, 2009, 10:34:36 PM »
They export the elevated polyline contours from Terramodel and then bring them into C3D.  We then create a new blank surface and just add the elevated polylines as contours in order to get 'Terramodel' contours in C3D.  Then, they start complaining about why the company decided to switch to C3D because it is generating false contours.  My questions is, who is to decide what contours are correct?  Just because you've used an application for many years and it generates smooth, flowing contours that a 'hand-draftsman' would generate doesn't mean that the surface is correct.  And I think that a lot of the complaining about C3D is due to insufficient training from Avatech.  Avatech likes to give un-realistic scenarios that have been designed in an office and tested over and over again to make sure the session will go smooth and error-free.  If you try to ask a question about doing something else, forget about it.  They just ignore your question and move on.

And Michael, believe me, as soon as the company is willing to spend the cash, I will do my best to get you in here for a week or so.  If Sinc enjoyed your session, I'm sure that we could benefit greatly from it as well.  :-)

I wish Autodesk would just buy up Terramodel and put this whole thing to rest!

mjfarrell

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Re: Contour Battles
« Reply #7 on: June 11, 2009, 11:11:16 PM »
Randy,

Do me a Favor if you can.  A blanket NON Disclosure is implied.

Send me a Point file, and or the breakline file from an example file.
Send me a PDF plot of the Terramodel version of this surfaces contours.

Let me run the data here and report back to you.

Be your Best


Michael Farrell
http://primeservicesglobal.com/

mjfarrell

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Re: Contour Battles
« Reply #8 on: June 12, 2009, 12:17:15 AM »
I think that there might be an easy process change, should you have the Trimble Geomatics Office product on hand.

The suggestion is that you export the surface model into Trimble Geomatics Office; then from there you export the LandXML version of the surface, and then use that inside C3D.  Minimum net effect should be a smoother, and time efficient process.

I also suspect that breakline data or lack thereof is playing a large part in the contour variations.
Be your Best


Michael Farrell
http://primeservicesglobal.com/

drizzt

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Re: Contour Battles
« Reply #9 on: June 22, 2009, 04:46:39 PM »
I use Terra Model (not by choice either). You should just "loose" the hardware lock!?

Dent Cermak

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Re: Contour Battles
« Reply #10 on: June 22, 2009, 10:48:04 PM »
I started out "hand drawing" contours. Generated by spot shots or off aerial photography. Initially , I then engraved them on a scribecoat with a sapphire tipped engraving tool. I have been drawing contours longer than most here have been drawing breath. If your Boss thinks terramodel produces "accurate" contours he is sadly mistaken. Smooth does not necessarily equate to accurate.
The trick is to learn how to edit your tin file until the contours are doing what they should and look smooth BEFORE applying any smoothing factors. You can do that in LDD and in Civil 3D and their smoothing routines "fit" the contours smoothly through the spot shots. Terramodel doesn't hold the points as well. It goes for looks (kinda like "fit" vs "spline").
The secret is being trainned on the software you are using and knowing how to fine tune the tin file. If you are guessing, you won't get it right.
There are not that many school trained cartographic drafters out there any more, but there are a lot of people pulling contours. Just because they look good does not make them more accurate. (Quick clue on if someone really knows contours.......do they know the definition of a depression contour and how to symbolise one properly? Do they know the symbol and how to create it? One or two programs do this, most ignore them because the programmers do not know about them. Programmers?PFFFFTTTT!! They came up with Major and Minor contours!! Bunch of yoyos!).
If you are looking to me for answers, you really have problems. Carlson Survey 2016 w/ Embedded AutoCad