AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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doni49
Posts: 1,656
Registered: ‎12-22-2012
Message 1 of 19 (292 Views)
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SAC: Intersection Point. Point not found?

292 Views, 18 Replies
12-19-2013 07:39 AM

I have a custom SA that I created in SAC 2012. 

 

It has an AuxSurfaceLink (AL1) and an AuxLink (AL10).  Then I have an "Intersection Point" (AP13) that is set to the intersection of these two links.  When my corridor tries to rebuild, I get an error message that AP13 could not be created at station 2+05.

 

I opened the Section Viewer and see no reason for the point not to be created.  If you look at the following image, it is a screen shot of the section at 2+05.  The white lines are what I drew in there manually.  AP13 should not be a problem.SAC SurfaceLinkIntersection.png

Don Ireland



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Make a version with real points, and let's see where they line up. AP5 may be ending up below the surface offset.

Thanks for all the assistance! 

 

As I already said, once I used your suggestion of adding points to see if/where they fell, I found that it really was having trouble locating the intersection point.  I'll go back and mark that reply as a solution as it was PART of the solution and without it, I wouldn't have found the problem.  It'll be important for people having similar issues to see that.

 

Anyway, I figured out how to use AP5's location to identify the desired depth.  First, here's a screenshot of the graphic I made to help me figure it out.

 

 

 

SAC SurfaceLinkIntersectionSolved.png

 

First I know that the angle between link L11 and line AP4-AP5 will ALWAYS be 90.  So I used that to figure out the angle between line AP4-AP5 and the vertical (in this case that angle is 43 which I'll call THETA).  I changed AP13 so that it is relative to AP4 at an angle from the vertical of THETA divided by 2 and a distance of 10.  Then I made an AUXLINK (AL15) from AP4 to AP13.  The intersection of AL15 and AL10 gives me the exact point where I want the bottom of my material to intersect with AL10 -- that's AP29.

 

Lastly, I changed the surface link definition's DEPTH to AP29.distancetosurface(Surface).  Since the depth is specifically controled by the distance from the point up to the surface, I'm guaranteed that it will go through the point (as long as the surface is actually above it).

 

The whole corridor is working without even a single error.

 

EDIT:  To figure out the THETA angle, I used math.acos(AP4.slopeto("AP5")).

Valued Mentor
fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 2 of 19 (285 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 07:57 AM in reply to: doni49

Auxillary Points and Links do not get created in the Civil 3D modeling environment.

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
Contributor
MKearney028
Posts: 20
Registered: ‎08-27-2010
Message 3 of 19 (271 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 08:40 AM in reply to: doni49
We need more details, but if AL10 cannot hit AL1 within the surface limits, it will give you that error. Surface links have a hard time with extensions.
So how is AL10 being created?
There may be an error before AP13 that is not allowing the subassembly to continue to be created.
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doni49
Posts: 1,656
Registered: ‎12-22-2012
Message 4 of 19 (259 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 08:48 AM in reply to: fcernst

fcernst wrote:

Auxillary Points and Links do not get created in the Civil 3D modeling environment.


I know that.  But the SA uses the AuxPoints and AuxLinks to create points and links that C3D DOES create.  The first error message in Panorama says that AP13 was not created.  Then there are several error messages about other points and links not being created but those depend upon AP13.  Once AP13 is works, the others should go away.  And this is ONLY happening at 2+05.  The corridor is 290 ft long and the frequency is set to 5 ft.

 

EDIT:  Here's a screen shot of Panorama.

SAC SurfaceLinkIntersectionPanorama.png

Don Ireland



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doni49
Posts: 1,656
Registered: ‎12-22-2012
Message 5 of 19 (258 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 08:49 AM in reply to: MKearney028

MKearney028 wrote:
We need more details, but if AL10 cannot hit AL1 within the surface limits, it will give you that error. Surface links have a hard time with extensions.
So how is AL10 being created?
There may be an error before AP13 that is not allowing the subassembly to continue to be created.

I understood that which is why I examined where AP13 should be created.  In the cross section editor, I used the same criteria that I defined the SA to use and manually drew the lines that the assembly should be creating.

Don Ireland



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fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 6 of 19 (247 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 09:07 AM in reply to: doni49

If that white line you drew is AL10, I don't see any surface intersection?

 

What surface is it suppose to intersect with? Is one of the red lines your target surface?

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
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doni49
Posts: 1,656
Registered: ‎12-22-2012
Message 7 of 19 (237 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 09:18 AM in reply to: fcernst

Here's a screenshot of the preview window from SAC.  This should help you understand what I'll try to explain.

 

AL1 is an AuxSurfaceLink with a DEPTH of 2ft.  So in the Section Editor, I drew a polyline on top of the surface and moved it down 2 ft.

 

AP5 is a point created by going from AP4 (the slope daylight point) and turning 90 degrees (referencing the bottom of the ditch (P17).  Then P16 is the bottom of the material layer below point P17.  This is seen in the previous screen shot as the location where my white line meets the yellow line (C3D created the yellow line correctly).

 

AL10 is created between AP5 and P16.

 

AP13 is SUPPOSED to be the intersection of AL10 and AL1.

 

SAC SurfaceLinkIntersectionPreview.png

Don Ireland



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doni49
Posts: 1,656
Registered: ‎12-22-2012
Message 8 of 19 (232 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 09:21 AM in reply to: doni49

Attached is a dwg file with my surface, alignment, profile and corridor.

Don Ireland



If a reply solves your issue, please remember to click on "Accept as Solution". This will help other users looking to solve a similar issue. Thank you.


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Valued Mentor
fcernst
Posts: 1,104
Registered: ‎01-07-2011
Message 9 of 19 (221 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 09:59 AM in reply to: doni49

Make a version with real points, and let's see where they line up. AP5 may be ending up below the surface offset.

Fred Ernst, PE
C3D 2015
Ernst Engineering
www.ernstengineering.com
*Expert Elite*
doni49
Posts: 1,656
Registered: ‎12-22-2012
Message 10 of 19 (214 Views)

Re: SAC: Intersection Point. Point not found?

12-19-2013 11:08 AM in reply to: fcernst

Nice troubleshooting suggestion.  I'll have to remember that one.

 

I created a point (P23) with a delta x and delta y of 0 relative to AP5 (basically making it on top of AP5).  Then to make the points stand out, I created two additional points (P22 and P21).  I added links between P22 & P16, P16 & P23, and P23 & P22.  I also made a SurfaceLink (not an aux) on top of AL1.

 

Here's a screenshot of the preview window with those changes.

 

SAC SurfaceLinkIntersectionPreview2.png

 

After saving and importing the updated SA, here's what the cross section editor shows.  You're right, AP5 IS below the AuxSurfaceLink and even with "Extend Link" turned on, it will not improve.

 

Now I need to figure out WHY that is.  When I manually drew the line work using the criteria specified in the SA, it works fine.

 

Thanks for all the help!

 

SAC SurfaceLinkIntersection2.png

Don Ireland



If a reply solves your issue, please remember to click on "Accept as Solution". This will help other users looking to solve a similar issue. Thank you.


Forum links:
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Civil 3D General
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