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Extend a 3DPOLY to a surface

17 REPLIES 17
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Message 1 of 18
anogramatic
3708 Views, 17 Replies

Extend a 3DPOLY to a surface

I am trying to extend several 3D Polylines to where they intersect a single surface.  

 

I haven't been able to figure out a quicker way of doing this than by drawing a construct 3D polyline between the top and toe of the slope I want to extend up to for each 3D Polyline I want to extend, then trimming where these two lines intersect...

 

Is there really no way to utilise the surface for extending / trimming 3D Polylines?

 

I am using a 64 bit machine with AutoCAD Civil 3D 2013 on Windows 7.

 

Any advice would be much appreciated

17 REPLIES 17
Message 2 of 18
neilyj666
in reply to: anogramatic

Use featurelines rather than 3D polys and assign the levels from the surface?

neilyj (No connection with Autodesk other than using the products in the real world)
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AEC Collection 2024 UKIE (mainly Civil 3D UKIE and IW)
Win 11 Pro x64, 1Tb Primary SSD, 1Tb Secondary SSD
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Message 3 of 18
anogramatic
in reply to: neilyj666

Hi neilyj,

 

This isn't quite what I'm after.

 

The levels of the 3D polylines are set.  I just want them trimmed to where they cross the surface plane.

Message 4 of 18
neilyj666
in reply to: anogramatic

I see, you are trying to locate a vertex at the point where the 3D poly passes (or would pass) through the surface?

I'm not sure this is possible directly but hopefully someone will prove me wrong.

The only workaround I've used previously is to ensure the 3D polys extend beyond the surface, then create a surface from the 3d Polys then use Minimum distance between surfaces to create a polyline at the interface.

neilyj (No connection with Autodesk other than using the products in the real world)
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AEC Collection 2024 UKIE (mainly Civil 3D UKIE and IW)
Win 11 Pro x64, 1Tb Primary SSD, 1Tb Secondary SSD
64Gb RAM Intel(R) Xeon(R) W-11855M CPU @ 3.2GHz
NVIDIA RTX A5000 16Gb, Dual 27" Monitor, Dell Inspiron 7760
Message 5 of 18
BrookeCSU
in reply to: neilyj666

You can create a feature line perpendicular to the 3Dpolys and grade to the surface horizontally. Will this work in your case?

Message 6 of 18
anogramatic
in reply to: BrookeCSU

Hmm, I don't think doing this will identify where the 3D Polyline would cross the surace?

Message 7 of 18
tcorey
in reply to: anogramatic

Can you draw me a picture or post a drawing just so I can be sure I understand the issue. I might be able to do something with vlisp.



Tim Corey
MicroCAD Training and Consulting, Inc.
Redding, CA
Autodesk Gold Reseller

New knowledge is the most valuable commodity on earth. -- Kurt Vonnegut
Message 8 of 18
anogramatic
in reply to: tcorey

Hi tcorey.

 

I've attached a picture below.

 

In this case I am trying to extend the magenta 3D Polylines to the surface.

 

 

3dpoly to surface.png

Message 9 of 18
tcorey
in reply to: anogramatic

Sorry to get your hopes up. I took a look at it and it would take me too long to write the code.

 



Tim Corey
MicroCAD Training and Consulting, Inc.
Redding, CA
Autodesk Gold Reseller

New knowledge is the most valuable commodity on earth. -- Kurt Vonnegut
Message 10 of 18
HansSMS
in reply to: anogramatic

If you joined the ends of your magenta lines with a feature line, graded this feature line horizontally to the surface, and then extend the magenta lines to the feature line created on the surface using the trim function (maybe exploding it to a polyline first) ?

Hans Moller
Surveying & Management Services
Gladstone Australia
Metabox 16GB, Intel i7-9700K 3.6Ghz, 500GB SSD, 2TB HDD Nvidia GTX 1060
AutoCAD Civil 3D 2018
Message 11 of 18
neilyj666
in reply to: HansSMS

This would only really work if the joined ends graded horizontally as if the final segment of each 3D poly was at a different grade which needed to be maintained it would give erroneous results.

neilyj (No connection with Autodesk other than using the products in the real world)
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AEC Collection 2024 UKIE (mainly Civil 3D UKIE and IW)
Win 11 Pro x64, 1Tb Primary SSD, 1Tb Secondary SSD
64Gb RAM Intel(R) Xeon(R) W-11855M CPU @ 3.2GHz
NVIDIA RTX A5000 16Gb, Dual 27" Monitor, Dell Inspiron 7760
Message 12 of 18
troma
in reply to: HansSMS

You could use a grading to target the surface. You would have to make a small featureline perpendicular to the end of your source 3Dpoly, place it at the end of your source 3Dpoly (x, y, z location) and then make the grading. You have to check the %grade of the source 3Dpoly and manually type it in so that you grade at the same slope.

Mark Green

Working on Civil 3D in Canada

Message 13 of 18
HansSMS
in reply to: neilyj666

Sorry, overlooked that there was a grade involved, haven't done this recently.

 

Over the last few years I have often wished there would be a function to intersect a line with a surface, it would be a great help for developing a design, just to see where a pipe or road CL was headed in relation to a surface. Ended up creating this little horizontal feature line at 90deg to the CL, and projecting (grading) it on to the surface. Attaching a road cross section to the end of the CL and grading that to the surface achieves the same thing.

Hans Moller
Surveying & Management Services
Gladstone Australia
Metabox 16GB, Intel i7-9700K 3.6Ghz, 500GB SSD, 2TB HDD Nvidia GTX 1060
AutoCAD Civil 3D 2018
Message 14 of 18
anogramatic
in reply to: troma

After having a similar issue on a different project today, I did a quick google search and came across my old post here.  Your solution effectively gets the point I need and is simple enough to do. Thanks.

Message 15 of 18
jmayo-EE
in reply to: troma

I use the grading object method but sometimes I may also use the zero contour. Take the 3d polys and place them in a surf. Run a vol srf between the the two surfaceas and extract the zero contour. This is the trim line for the 3d polys.

 

Not much of a time savings but I sometimes want that zero contour for limit of grading or other boundary needs.

John Mayo

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Message 16 of 18
Neilw_05
in reply to: troma

This challenge was presented in another recent thread. A couple of solutions were offered. One that you might find useful utilizies a daylight grading but in a different way. You can review the approach in my replies to the thread found here:

 

http://forums.autodesk.com/t5/autocad-civil-3d-general/how-can-i-trim-a-line-that-goes-throw-a-3d-fa...

 

I'm not saying it is a better solution but it may be simpler in some ways.

Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com
Message 17 of 18
jmayo-EE
in reply to: jmayo-EE

I forgot to add a step. You will probablt need to use the lengthen command on the 3d polys befrore building the surface. Lengthen them any distance that extends them beyond the base/eg surface.

John Mayo

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Message 18 of 18
Neilw_05
in reply to: jmayo-EE

To add to John's comment about the lengthen tool, the lengthen command will extend the 3d polyline end segment along it's projected slope. Thus it is a good way to extend the polylines without having worry about affecting it's slope. Use the Delta option to add X units of length to the ends if you need to extend them enough to pass through the target surface.
Neil Wilson (a.k.a. neilw)
AEC Collection/C3D 2024, LDT 2004, Power Civil v8i SS1
WIN 10 64 PRO

http://www.sec-landmgt.com

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