Route finding and analysis

[Anonymous]

I have the task of finding routes through hilly terrain that are not to
exceed 12% grades. I would like some ideas on workflow and tools to achieve
the task efficiently.

My first approach has been to define an alignment and sample the terrain to
build an EG profile and then use the EG profile to build a corridor to get a
rough look at slopes, daylighting and volumes. I can then manipulate the
alignment graphically and get immediate feedback since the corridor will
update according to the EG profile. A couple of drawbacks to this approach
are:

1) Using the EG profile for FG makes the corridor follow the terrain too
closely to get a somewhat realistic result. Ideally I would like to just
match EG at key points along the alignment such as at PC's and PT's or at
any intermediate PI's along the alignment. Thus by adding a vertex along a
tangent I can manualy create a sample point in large fill or cut areas to
tweak the profile. To manually create an FG profile would be too tedious
since it would become invalid every time I tweaked the alignment. I'm
looking for ideas on how to create a dynamic profile at the key points for
the proposed roadway.

2) The EG profile is too dense to use profile tangent labels to analyze the
slopes. One solution here is to use plan view slope analysis to shade the
surface built from the corridor or use slope inquiries or labels on the
surface model. I'm open to other ideas here. The ideal is to get immediate
dynamic feedback when making adjustments to the alignment.

3) I would like the corridor to have a vertical offset such as 1 foot above
EG rather than matching grade at the centerline. I am still new to C3D so
I'm not sure how best to achieve this. Perhaps I can design the offset into
the assembly or somehow apply it to the profile. Again I am looking for
suggestions here.

This is my intuitive approach to the challenge based upon my limited
knowlege of Civil 3D. There may be other ideas that would work better so if
you have some experience in this regard please share your ideas.

TIA,
Neil

[Anonymous]

"...The EG profile is too dense"
You can add grade labels to your EG profile and yes the labels will be too
close together, EXCEPT if you specify the "Weeding" value wide enough. Edit
the EG profile labels and scroll all the way to the right and change the
value for weeding.

I do a combination of a slope analysis style on the EG surface so I can see
what's 12% and less AND grade labels on the EG profile. I tweak the
alignment so that the EG under it meets the greade requirements without
creating a corridor.

When I have it about right then I rough in an FG profile and I can snap to
any EG points I wish. Yes you'll need to tweak the profile every time you
adjust the alignment, but I think thats about it.

Matt

[Anonymous]

The weeding helps Matt. thanks for the tip.

As an update on this task: I tried using projection grading to do this task
but it is way too slow to update when I tweak a vertex..and that is without
using automatic surface creation.

"Matt Kolberg" wrote in message
news:5802299@discussion.autodesk.com...
"...The EG profile is too dense"
You can add grade labels to your EG profile and yes the labels will be too
close together, EXCEPT if you specify the "Weeding" value wide enough. Edit
the EG profile labels and scroll all the way to the right and change the
value for weeding.

I do a combination of a slope analysis style on the EG surface so I can see
what's 12% and less AND grade labels on the EG profile. I tweak the
alignment so that the EG under it meets the greade requirements without
creating a corridor.

When I have it about right then I rough in an FG profile and I can snap to
any EG points I wish. Yes you'll need to tweak the profile every time you
adjust the alignment, but I think thats about it.

Matt

[SageRoot]

I create a surface style with a 12' contour interval (interval to match the grade that I am shooting for). Then I just draw a 100' radius circle from where I want to start, draw a line from the center of the circle to the intersection of the circle and the next contour up or down in the direction that I am working. Move your circle to the end of your new line and do it again. You will need to swing a little wide in preparation for a switchback if needed (you will get the hang of it after a while).

After I get all of these lines drawn, I use them as a rough guide for my alignment. Your FG profile will match your EG fairly close.

I suppose that if you need to match the EG any better you could use a 6' interval and a 50' circle.

Have fun.

Sage

[Anonymous]

Great idea Sage! I'll give this a look.

wrote in message news:5802913@discussion.autodesk.com...
I create a surface style with a 12' contour interval (interval to match the
grade that I am shooting for). Then I just draw a 100' radius circle from
where I want to start, draw a line from the center of the circle to the
intersection of the circle and the next contour up or down in the direction
that I am working. Move your circle to the end of your new line and do it
again. You will need to swing a little wide in preparation for a switchback
if needed (you will get the hang of it after a while).

After I get all of these lines drawn, I use them as a rough guide for my
alignment. Your FG profile will match your EG fairly close.

I suppose that if you need to match the EG any better you could use a 6'
interval and a 50' circle.

Have fun.

Sage

[JeffPaulsen]

I do much like Sage described but I learned a way to avoid the circles. You can use dynamic input to see the length of the line segment. Before dynamic input I used the cursor coordinate values that are displayed on the status bar. You may have to click on the coordinate box on the status bar to change the display to relative coordinates.