Grading A Feature Line That Has Multiple Slopes

[civilengineer83]

I'm using Civil 3D 2019

The task:

I am trying to grade a feature line for a site down to existing and we have a few areas where a 3:1 slope will not work for us. So in those areas, we're attempting to grade those back at a 2:1 slope. I start with my feature and select that I do not want to apply the grading to the entire line, so I can pick from station 0+00 to where my first transition is and create a 3:1 slope. Next, I select the feature line again, and pick up where I left off, creating a 50-ft transition and pick the next transition location where I'll be switching back to 3:1.

The Issue:

At some locations, after picking all my start/end points, I'm not getting any grading at all. I can tell immediately because the feature is so long, that it can take quite a few seconds to produce the grading. When this is happening, it's instantly finishing with no grading produced. I can do this by creating full-length feature line grading at 3:1 and 2:1 slopes individually, but then splicing and piecemealing the toe can be rather laborious. It also means I have to go around the entire toe and delete the extra lines Civil 3D so lovingly adds to my surface. There a quite a bit of cut/fills around the toe, so creating a boundary to add to the surface can also be a daunting task.

Does anyone have any tips or tricks or can tell me what might be happening in my grading to cause a portion to just not show up, effectively producing no grading whatsoever?

[tcorey]

Are you aware that you can use a Feature Line as a Corridor Baseline? That will avoid the errant behavior you get from Gradings.

[steve.sadler]

Did you get an answer to this problem, I am having the exact same issue, and get it to work with multiple grades

regards

Steve

[steve.sadler]

I am having the same issue, just wondering if there is a way round it, extremely new to 3D civils so I am struggling a bit

regards

Steve

[civilengineer83]

Hey Steve, I did not get a response in time so had to work it out for myself. The task was daunting at best and a nightmare at worst, but I did find my own solution. What I did was I graded the portions of the line that needed 3:1 and the portions that needed 2:1 from the same feature line, leaving at least a 50-ft gap, but it was better if I could make it a 100-ft gap. I then used a transition between all of the 3:1 and 2:1 connections. You'll find that in the same tool bar that you're trying to grade from. Just drop down the type of grading you want, and select transition, then all you have to do is pick a location between the gradings you already did. I'm not familiar enough with corridors to figure out how to create multiple grading areas along the same corridor, so this option worked best for my site. I hope that makes sense.

Kind Regards,
Matt

[pperales2]

Did you guys check the automatic surface creation box?

[pperales2]

Also, can you post a pic like a diagram of what you are trying to do?

[pperales2]

This might depend on your grading criteria, you can grade to relative elevation, grade to elevation, grade to surface, and (I forgot the other one). What is you grading criteria and what is the layout of the site of which you are grading? This information is key to help you.

[cwitzel5NL5H]

I think two solutions I would pursue would be the corridor or multiple gradings.  Keeping the gradings separated is key.

I also often just draw a feature line by hand, where I know it will work and project it to the daylight surface.  

[civilengineer83]

Yes, I usually turn on automatic surface creation when I'm having to create what I would call an unusual grading entity. I don't turn it on when I'm constantly exploding the grading objects just to rob the the 3D polyline at the toe. Also, a lot of my grading objects overlap between two different surfaces, so that works best for me.

In regards to this project, I was grading from a feature line extracted from a corridor and grading down to existing.

[civilengineer83]

Yes, I haven't had as much experience trying to create multiple slopes along a corridor and ultimately would have taken me longer to figure out than just creating separate grading surfaces from the same feature line and then creating the transition between them with my surface generation turned on.

[pperales2]

Why would you explode a grading object? You can paste the grading object surface to the FG surface you are creating.

[civilengineer83]

Because a lot of the grading I do is very complicated. I've seen too many times CAD flip out on me and cause all sorts of strange things to happen in my drawings by pasting too much. I've seen feature lines and grading objects disappear and have to spend too much time trying to figure out what went wrong and where. Exploding the grading objects leaves me with 3D polylines that I can manipulate to create my surfaces from. As I said, when grading one feature line into 3 different surfaces it can get complicated real quick and with sites in excess of 150 acres at a time, I can't afford the time it takes to track down all of the missing pieces from something that got pasted when I can have the toe of slope lines that never give me heartburn.