AutoCAD Civil 3D General Discussion

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Member
A&Arjh
Posts: 4
Registered: ‎05-19-2005
Message 1 of 9 (65 Views)

Profile Intersections

65 Views, 8 Replies
05-19-2005 08:48 AM
If I have two alignments that intersect in a "T", and two corresponding profiles, how can I start the second profile at the same elevation of Finished Ground of the first profile? I tried Superimposing the profile of the first, but it does not display the profile at the correct elevation. There must be a way to extract the elevation at the station where the two alignments intersect, and use that as the start elevation of the second profile.
*Evan Williams
Message 2 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 09:57 AM in reply to: A&Arjh
Hi there,

Here's one quick way to get the elevation that you want to start the FG
profile for the intersecting road.

Let's call the two alignments A-1 and A-2, and the corresponding profiles
P-1 and P-2. A-1/P-1 represent the main road and A-2/P-2 represent the
intersecting road.

Get the station on A-1 where A-2 starts. You can do this hovering your
crosshairs over the intersection point on your plan view, zooming in a fair
bit, and read the intersection station on A-1 off the tooltip readout. Then
go to your P-1 profile view, and go through a similar process. Hover your
crosshair over the intersection station on your P-1 FG profile, zoom in, and
then read the elevation off the tooltip that pops up. Now knowing the
elevation of the main road FG profile at the intersection point, you can
proceed to laying out your P-2 FG profile.

You may want to change the precision for elevation (and stationing) in your
profile views---C3D seems to default to 2 decimal places, and I'd want at
least 3. If you're using C3D2006, click on the Toolspace "settings" tab,
right-click on the "Profile View" branch of the tree, and click on the "Edit
Feature Settings..." context menu choice. In the Edit Feature Settings
dialog that pops up, scroll down to the "Elevation" branch of the tree,
expand it, and change the "precision" setting to your liking. OK your way
back to your drawing. Your tooltip readout for elevation on the profile
view should now refelct the precision level that you've just set. You
should clearly see that you can adjust the settings for other things,
stationing, for example, in the same "edit feature settings" dialog.

There was a quirk in C3D2005 (at least in the version I have), where the
feature setting for elevation in a profile view was actually controlled by
the elevation setting for "Section View"---the profile view settings seemed
to have zero effect! So if you're using C3D2005, and you're not getting
anywhere by trying adjust the feature settings for profile views, try
adjusting the feature settings for section views.

Hope that this helps.

--- Evan


wrote in message news:4850551@discussion.autodesk.com...
If I have two alignments that intersect in...





Member
A&Arjh
Posts: 4
Registered: ‎05-19-2005
Message 3 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 10:10 AM in reply to: A&Arjh
That is what I was afraid of. This seems like something that should be a part of the program, without having to "eyeball" the Sta/Elev. C3D2006 is a wonderful tool, however it is basic design tools like starting an intersecting road at the same elevation as the main road that are really important.

Is it possible to add an automatic label with alignment name/sta (A-2/12+50.00) to the main profile where the intersecting road crosses?
*Don Reichle
Message 4 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 10:26 AM in reply to: A&Arjh
I hate to throw out an "old school" solution to you, but you know the
Station of the C/L intersection, correct. Subtract the station of the
Preceding PVI, and multiply the difference by the Grade. Add that product to
the Preceding PVI Elevation. The result should be the C/L intersection
Elevation.

I'm not trying to insult your intelligence with this, just providing a
work-around.

HTH

--
Don Reichle
"King Of Work-Arounds"
"The only thing worse
than training your staff,
and having them leave is -
not training your staff,
and having them stay."
Courtesy Graphics Solution Providers
--------------------------------------
LDT3/CD3
IntelP4-2.4
1GB RAM
Intel 64MB


wrote in message news:4850698@discussion.autodesk.com...
That is what I was afraid of. This seems ...






Member
A&Arjh
Posts: 4
Registered: ‎05-19-2005
Message 5 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 10:33 AM in reply to: A&Arjh
True, but it becomes a little more complicated in a vertical curve. Yes, there are equations to determine the elevation, but that's not the point. C3D obviously knows everything about the alignments & profiles, and I should be able to easily extract the data to do the design. There needs to be more inquiry/label tools, and certainly more design tools like "begin profile at alignment intersection and elevation of intersecting profile" (okay, that name's a little too long for a command, but you get the gist).
*Evan Williams
Message 6 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 10:55 AM in reply to: A&Arjh
Hi,

"Eyeballing" to within a millimetre for the design is accurate enough for
me---especially given that when the pavement gets laid (not to mention that
after years of trucks rolling over it and frost heaving it), it will
probably be centimetres different from the design.

I suppose that, when you create your P-1 FG profile, you could put a PVI at
the interesction location (provided that it's not within the length of a
vertical curve) with zero grade change on either side and entre whatever
elevation works. That way, you know from the start where your P-2 FG
starting elevation is going to be. You can easily label it, too.

If the intersection station occurs in a vertical curve (a perhaps
questionable general practice, though maybe occasionally unavoidable---on a
mountainous forest road, for instance), I guess that you have to rely on the
tooltip method or do a bit of math, as Don Reichle suggests.

--- Evan


wrote in message news:4850698@discussion.autodesk.com...
That is what I was afraid of. This seems ...






Member
A&Arjh
Posts: 4
Registered: ‎05-19-2005
Message 7 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 11:09 AM in reply to: A&Arjh
The issue is not precision. The issue is a lack of intuitive, useful design tools. I have no problem being within hundredths of a foot on my profile designs. What I have a problem with is a program that makes me use work-arounds to do a task that I need to accomplish on a frequent basis.
Contributor
quiggle
Posts: 19
Registered: ‎05-05-2005
Message 8 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 11:36 AM in reply to: A&Arjh
One could also make a PI in the alignment at the intersection which could be labeled as ahorizontal geometry point. If the intersection falls within a horizontal curve you can define it as a PCC with the same results.
*Don Reichle
Message 9 of 9 (65 Views)

Re: Profile Intersections

05-19-2005 11:43 AM in reply to: A&Arjh
snip>What I have a problem with is a program that makes me use work-arounds
to do a task that I need to accomplish on a frequent basis.

Sounds like you've not spent much time with the predecessor - LDT.

Hence my aka. :-)

Since people aren't perfect, and the pool of programmers come from that
group, my position is that (good, bad or indifferent) Work-Arounds are just
a fact of life.

HTH

--
Don Reichle
"King Of Work-Arounds"
"The only thing worse
than training your staff,
and having them leave is -
not training your staff,
and having them stay."
Courtesy Graphics Solution Providers
--------------------------------------
LDT3/CD3
IntelP4-2.4
1GB RAM
Intel 64MB


wrote in message news:4850799@discussion.autodesk.com...
The issue is not precision. The issue is ...


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