Creating Roads

[spittle]

I've never done this before so have a few queries.

 

Attached are two JPEGs showing my proposed Site Layout and a section of the proposed access road.

 

I have an existing 3D surface for the entire area (switched off for clarity). I now need to create a proposed surface.

 

How hard would it be to create a C3D road following the exact curves of the one I have drawn in cad? (curves are defined by Autotrack akllow access for articulated vehicle)

 

Currently I'd use feature lines to draw the road edge and model it into my surface but it's a rubbish way of working as when the layout changes it's a real ****** to move everything around.

 

Ideally I'd like to:

 

- model my proposed surface

- grade this into my existing surface

- then create a proposed access road (including the loop)

- then grade this into both surfaces.

 

- I'd then like to have the option to be able to rearrange my site layout and move my road to suit.

 

Can I do this?

 

Any tips would be appreciated. Or an 'in-a-nutshell' summary.

 

 

Cheers

[lpseifert]

In a nutshell...

1. create an existing surface

2. create an alignment

3. create a profile

4. create a corridor

 

all subjects covered in the tutorials supplied with Civil 3D (Help > Tutorials)

[rustysilo]

And you might add a 4a. which would be to create your assembly(s) (cross section template) which is what you will use to create the corridor.

[spittle]

Thanks guys, had a scan over the tutorial and will hopefully try when I get time.

 

Currently we don't need to put any real effort into the design of the road so I can't spend much time on it. I'm just trying to reduce the amount of time spent reworking my surfaces and just need a quick solution.

 

In your experience is this a good approach for this?

 

all I know about the road is the levels around the loop, and that it needs to roughly follow the existing ground profile.

 

Is this pretty easy? How long would it take you guys to do this?

[lpseifert]

It's not hard once you learn a bit about C3D; probably for a draft it would take 2-3 hrs depending on the data you have for existing surface/ the topo and the detail needed.

[rustysilo]

You have to find your own "groove" when it comes to the tools and process you use. It can be accomplished with either feature lines and gradings, a corridor, or a combination. This looks like it would actually be a very simple one to do and like Seifert says, it would take a few hours.

[spittle]

And say at a later date you have to increase the size of the loop a bit, and increase the radius of some of the bends. What's involved in this? Is it just dragging points arround?

 

Also could you have the carpark included on the road design and the reverseing space for the truck shown on JPEG1? And is this easy enough to learn?

[rustysilo]

Edit's would be fairly easy. The tricky parts would be the 3 way intersection and then the carpark and truck spot (depending on how you decided to model them).

 

I'm not sure which part is the carpark? Looks like it is the upper right part of the loop? The truck spot I'm guessing is the place on the left?

[spittle]

I finally had time to create my first road corridor.

 

Now I'm trying to create a coridor surface so that I can create a grid volume surface. It appears to create the corridor surface ok, but when I try to create the volume surface it says 'Error Creating Surface'.

 

the only thing I can see as a potential error on my cut and fill for my corridor is there are a few gaps as you can see in the attached JPEG.

 

Any ideas?

 

The problem appears to occur when there is a transition between cut & fill.

[rustysilo]

Please explain how you went about creating the corridor and volume surfaces.

 

As far as the gaps in the corridor it appears that maybe the corridor did not intersect the existing ground surface at those points/areas.

[spittle]

I had a surface,

I drew an alignment (Not using curves - I'm wondering if this is the culprit - though I don't think so)

I created a long section for this alignment displaying my surface.

 

I then drew my proposed road profile on my longsection

 

I then turned the polylines indicating either side of my road into two more alignments (this time using curves)

 

I then created an assembly, a bit of road, cut & fill, and then mirrorred them both.

 

I created the corridor which cut and filled where it needed to.

 

I then created a corridor surface.

 

tried a Volume TIN, and it failed. Potential culprit I can think of is the gaps between the cut and fill off my road corridor.

 

Attached is a JPEG showing how it looks in plan with my main surface's triangles turned on.

[spittle]

Here's another JPEG of my main surface rotated to show that the cut/fill should have intersected the main surface

[rustysilo]

Hard to say without seeing the file, or the data thereof, however the first thing I'd stab at would be adding a curve to the centerline alignment to see if that would fix the problem. I suspect that may be it, but again, hard to say without seeing or knowing more thoroughly how your ass'y is composed.

[spittle]

I've had a thought... the subassemply part I used for the cut/fill on the edge of my road is the BasicSideSlopeCutDitch - "cut or fill daylight sideslopes with a ditch in cut situations". I didn't want the ditch and couldn't see a standard cut/fill sub assembly so I just set those perameters to 0 width.

 

I'm thinking though perhaps the trouble spots are because the ditch can't grade to the cut? I really don't know what the problem is.

 

I tried a curved alignment without success so have reverted back to the original one.

[rustysilo]

You might be on to something with that thought.

[spittle]

All sorted - the problem was under my surface tab in Corridor Properties I hadn't added a link to the surface. I don't understand exactly what I did, but I added a link to TOP and it worked.

 

The solution was found on theswamp forum.

[rossuwp00]

I've been working on creating a corridor for a while now, and am having a weird error.

 

I've created the surface, alignment, profile, and assembly. However, when I try to create a simple corridor, nothing happens. I can see in Prospector that there is a corridor created, however nothing appears. I've made sure all layers are on, and nothing. Any thoughts?

 

update: I wasn't attaching my subassemblies to my assembly.

[sinc]

All sorted - the problem was under my surface tab in Corridor Properties I hadn't added a link to the surface. I don't understand exactly what I did, but I added a link to TOP and it worked.

 

You didn't add a link to TOP, you added a TOP link.

 

If you look in your subassemblies, each link can have one or more codes assigned to it. For some subassemblies, these codes are pre-assigned, and you cannot change them (the help lists all the link codes for each subassembly). For other subassemblies, you can assign link codes via the subassembly properties.

 

Then, you can create a surface by adding lines from the corridor. The "links" are lines perpendicular to the corridor baseline, while the "feature lines" are the lines that run longitudinally from station to station in your corridor. (Note that you can turn on and off feature lines, by specifying which point codes get linked into feature lines on the "Feature Lines" tab of the Corridor definition.)

 

You created a Corridor Surface, then as part of its definition, you added the "TOP links". This means that every link that is coded with a "TOP" code will be used as a breakline in your corridor surface. Sometimes, you might get some garbage in your surface, such as along curbs. So you can sometimes get better results by also adding some feature lines to your surface as additional breaklines, to clean up some things. You can also use overhang correction, to specify how the surface should be built if two links with the same code exist at the same point. "Inward" and "Outward" branching help control how the feature lines are created. All of this together gives you the power to create various surfaces from your corridor.

 

For example, you may want to create a TOP surface using all the TOP links, and a DATUM surface containing all the DATUM links. Then you could compare the TOP and DATUM surfaces, and come up with a volume between them. (Note that some links, such as the generic links and daylight links, may include both TOP and DATUM codes on the same link; in that case, that link would be used in both the TOP surface and the DATUM surface.)

 

This is just a brief overview of some of this stuff; there's more.