AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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Active Member
caruga1
Posts: 7
Registered: ‎04-29-2011
Message 1 of 10 (880 Views)
Accepted Solution

Offset TIN surface

880 Views, 9 Replies
03-15-2014 04:41 AM
Hi, everybody! I would like to know is there any possibility to create offset surface from existing TIN surface (not rise / lower) ? Thanks!
*Expert Elite*
wfberry
Posts: 1,832
Registered: ‎09-05-2006
Message 2 of 10 (863 Views)

Re: Offset TIN surface

03-15-2014 06:00 AM in reply to: caruga1

What does offset mean, laterally?

 

Export surface via LandXML.  Rename current surface.  Import LandXML.

 

I am sure you can just move it laterally, I have had no reason to try it.

 

Bill

 

 

Active Member
caruga1
Posts: 7
Registered: ‎04-29-2011
Message 3 of 10 (850 Views)

Re: Offset TIN surface

03-15-2014 07:36 AM in reply to: wfberry
Hi, wfberry! Maybe I wasn't clear enough - i have to offset existing surface normal to itself, not move it laterally - but can't realize the way to do it in C3D... I can extract triangles from existing surface and than offset them using surfoffset command and create TIN again, but this method is not very accurate and it is time consuming. I'm looking more automatic and more ACCURATE way to do it... Let say that offset surface represent excavation line and has to be very accurate in this case.
Valued Contributor
SkipBurns
Posts: 70
Registered: ‎06-25-2008
Message 4 of 10 (825 Views)

Re: Offset TIN surface

03-15-2014 11:42 AM in reply to: caruga1

I'm a little confused by your explanation, but I think that what you are trying to do is create a copy of the existing surface that is lowered by a certain amount.

 

If so, create a new surface and use edit-"paste surface" to paste the existing surface into that one.  Then use edit-"raise/lower surface" to lower that surface by the amount.

 

You will then have two surfaces.. the existing.. and the "excavation" surface.

Active Member
caruga1
Posts: 7
Registered: ‎04-29-2011
Message 5 of 10 (814 Views)

Re: Offset TIN surface

03-15-2014 01:20 PM in reply to: SkipBurns
I would like to create surface to be offset normal to the triangle faces of existing surface. I posted picture below that illustrate difference between offset and rising / lowering. In the First picture is shown what I'm trying to achieve. Thanks!
Active Member
caruga1
Posts: 7
Registered: ‎04-29-2011
Message 6 of 10 (807 Views)

Re: Offset TIN surface

03-15-2014 01:25 PM in reply to: caruga1

Here is the picture :smileyhappy:

*Expert Elite*
Neilw
Posts: 2,247
Registered: ‎09-04-2006
Message 7 of 10 (786 Views)

Re: Offset TIN surface

03-15-2014 01:56 PM in reply to: caruga1
This question has been raised several times in the forums. Try a search for offset+ surface+normal.

AFAIK there is no way to do it.
Neil Wilson (a.k.a. neilw)
Infrastructure Suite/C3D 2013, LDT 2004, Power Civil v8i SS1
WIN 7 64 PRO
HP Pavillion h8xt, i7 2600, 12 GB
RADEON 6450, 1 GB
http://www.sec-landmgt.com
Active Member
caruga1
Posts: 7
Registered: ‎04-29-2011
Message 8 of 10 (774 Views)

Re: Offset TIN surface

03-15-2014 03:30 PM in reply to: Neilw
Thanks!
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Joe-Bouza
Posts: 4,884
Registered: ‎12-15-2008
Message 9 of 10 (770 Views)

Re: Offset TIN surface

03-15-2014 03:45 PM in reply to: caruga1

caruga1 wrote:
Hi, wfberry! Maybe I wasn't clear enough - i have to offset existing surface normal to itself, not move it laterally - but can't realize the way to do it in C3D... I can extract triangles from existing surface and than offset them using surfoffset command and create TIN again, but this method is not very accurate and it is time consuming. I'm looking more automatic and more ACCURATE way to do it... Let say that offset surface represent excavation line and has to be very accurate in this case.

No kidding. What happens when two normal vectors intersect at the offset distance? Or diverge and the surface area gets larger? sounds undefined and redefined to me.

What are you building that a datum excavation wouldn't give a close enough representation of the volume?

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People) Civil 3D 2012 & 2013
HP Z210 Workstation
Intel Xeon CPU E31240 @ 3.30 Hz
12 GB Ram


Note: Its all Resistentialism, so keep calm and carry on

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Active Member
caruga1
Posts: 7
Registered: ‎04-29-2011
Message 10 of 10 (747 Views)

Re: Offset TIN surface

03-16-2014 03:22 AM in reply to: Joe-Bouza

Joe-Bouza wrote:

No kidding. What happens when two normal vectors intersect at the offset distance?

Please, see picture I have posted in my earlier post.


I said that offset line represent excavation line not that i'am looking for excavation volume. What i'am looking for are new positions of grade brake points

on the offseted surface.

 

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