Grading to surface with multiple slopes

[Anonymous]

Hello, I'm working on a drawing where I need to design a cut at a 2:1 slope that later rounds to a 2.5:1 slope at the upper five feet. When I grade to surface, I can only input one slope for cut or fill. Does anyone know a way to work around this?

[samir_rezk]

Hi @Anonymous 

if we visualize a 100' Feature Line, I would create a grading object that is 2:1 for the first 5' of the feature line then create another grading object that is 2.5:1 for last 5' of the feature line. then simply create a transition grading object between the two short grading object segments

Hope this helps,

[Anonymous]

I probably should have put in a screenshot to show what I'm trying to do exactly. The surface with the white contours is the existing elevation. The red grading surface is what I made trying to grade to surface at a 2:1 slope. I need to round the last 5 feet of the cut to a 2.5:1 slope.

[samir_rezk]

Hello again,

thanks for the screenshot! If I understand correctly, you are trying to create a multi slope grading  object to the target surface... this is not possible with the grading tools unless you do some eloborate offsetting and exploding of feature lines to get the result you want! However a better option is to create a corridor to daylight to surface, this way you can make use of a daylight subassembly. Most subassembly do support inputting many slope and width parameters of your choice.

hope this helps,

[ChrisRS · Accepted solution]

I do not have time to check this but it should work.

So far, so good. We will work with your existing 2:1 cut slope.

1. Safety First! Grading objects ate toxic temperamental.
   1. Save your drawing. (This is a backup.)
   2. Save As and give your drawing a new name. Work with this drawing. When you have completed the grading successfully, you can Save As using the original name and overwrite your backup. 
      1. Purge, all.
      2. Audit, yes
      3. -Purge, registered apps, *, no
      4. Save this working drawing
2. You are at Figure "A" below. You have created the slope (1) and preliminary daylight point. The problem is that the location of the 5' wide green "rounding" is indeterminate. It is not 5' uphill (cyan) or 5' down hill (magenta).
3. Looking at the problem differently, as shown in Figure "B," we can determine the actual location of the daylight point. (Thanks to Katie Mercier)
4. Making use of this, as in Figure "C" requires use of 2 sites.
   1. We will say that what you have done so far (1) is in "Site 1"
   2. Create "Site 2" and a grading group "GG2" that is in Site 2. If you use an automatic surface for GG2, set it to display boundary only.
   3.  Step (2) - copy the feature line you used as a baseline for grading (1) to Site 2. 
   4.  Step (3) - working in site 2, use the new copy of the feature line as a baseline, and create a 5' grade (3) to distance at 2.5:1. this creates a new feature line (4) 5' uphill of the base FL.
   5. Step (5) - working off the new FL (4), grade to surface (EG) to create a slope (5) and FL (6) at the actual daylight location.
   6. Step (6) - copy the actual daylight FL (6) to Site 1. Slope 1 needs to be trimmed to create the rounding and trim away the shaded area.
5.  Figure "D" - Step (7) working in Site 1, and using FL (6) as a baseline, create a grade to surface at slope = 2.5:1 targeting the slope (1) surface. This creates slope (7), feature line (8) at the grade break and trims away the shaded area.
   (Alternately, Slope (1) is not needed; Slope 7 can be a 5' grade to distance at -2.5:1 followed by a grade to surface at -2:1 that would take the place of (1))
6. Check the rest of the drawing to be sure no previously created gradings have disappeared.
   1. If the drawing has become corrupt, close without saving and start over using a clean copy of the backup.
   2. If everythong looks good:
      1. Purge, all; Audit, yes; -Purge, registered apps, *, no
      2. Save this working drawing.
      3. Save As using the original name to replace the backup copy.

This could also be done using corridors. You would probably need custom subassembly that worked backwards to create some auxilary points.

Good luck! 

[Anonymous]

Right now, I'm stuck on grading to surface for site 2(Step 5). I left it running overnight and ACAD is still working on it. 

[ChrisRS]

It looks like civil 3D is hung. You will need to start over with a copy of your backup drawing. (Task manager, C3D, and task.)

 As I said, C3D is temperamental.

Save often. Purge, Audit, -Purge before saving.

The areas where there is fill instead of cut may be causing a problem. Try grading just the part of the line that is in cut.

As @samir_rezk  days, you may want to create a subassembly and use a corridor. This would be a little tricky. Start with a conditional and have suffered paths for cut and for fill.

For the fellow condition you adjust a light to the existing grade at your desired slope. For the cut condition you would set an auxiliary point -5 feet (out) at 2.5:1, then slope to EG at 2:1 to create the daylight point. Then 6 feet (in) at -2.5:1 to the grade break point. Then a link from the grade break to the starting point.

[Anonymous]

Deleted

[ChrisRS]

Hi, @Anonymous, I gat an email with your comment before it was deleted. I hope deleting it means that you were able to move forward on your own. I hope it worked for you.

If this method solved your problem, it is a good idea to mark it as a solution so that it shows up for future users. 

[sboon]

---

@ChrisRS wrote:

1.  

This could also be done using corridors. You would probably need custom subassembly that worked backwards to create some auxilary points.

---

Many of the OOTB daylight subassemblies include rounding options.

Steve
Please use the Accept as Solution or Like buttons when appropriate

[neilyj666]

The worklfow described by @ChrisRS would work in theory but as he suggested grading objects are notoriously buggy and unstable especially in this complex situation.

I would definitely use corridors which are more involved to set up but can use a feature line as a baseline and are much more stable

[Anonymous]

I ended up making a subassembly using ChrisRS's

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@ChrisRS wrote:

I do not have time to check this but it should work.

So far, so good. We will work with your existing 2:1 cut slope.

1. Safety First! Grading objects ate toxic temperamental.
   1. Save your drawing. (This is a backup.)
   2. Save As and give your drawing a new name. Work with this drawing. When you have completed the grading successfully, you can Save As using the original name and overwrite your backup. 
      1. Purge, all.
      2. Audit, yes
      3. -Purge, registered apps, *, no
      4. Save this working drawing
2. You are at Figure "A" below. You have created the slope (1) and preliminary daylight point. The problem is that the location of the 5' wide green "rounding" is indeterminate. It is not 5' uphill (cyan) or 5' down hill (magenta).
3. Looking at the problem differently, as shown in Figure "B," we can determine the actual location of the daylight point. (Thanks to Katie Mercier)
4. Making use of this, as in Figure "C" requires use of 2 sites.
   1. We will say that what you have done so far (1) is in "Site 1"
   2. Create "Site 2" and a grading group "GG2" that is in Site 2. If you use an automatic surface for GG2, set it to display boundary only.
   3.  Step (2) - copy the feature line you used as a baseline for grading (1) to Site 2. 
   4.  Step (3) - working in site 2, use the new copy of the feature line as a baseline, and create a 5' grade (3) to distance at 2.5:1. this creates a new feature line (4) 5' uphill of the base FL.
   5. Step (5) - working off the new FL (4), grade to surface (EG) to create a slope (5) and FL (6) at the actual daylight location.
   6. Step (6) - copy the actual daylight FL (6) to Site 1. Slope 1 needs to be trimmed to create the rounding and trim away the shaded area.
5.  Figure "D" - Step (7) working in Site 1, and using FL (6) as a baseline, create a grade to surface at slope = 2.5:1 targeting the slope (1) surface. This creates slope (7), feature line (8) at the grade break and trims away the shaded area.
   (Alternately, Slope (1) is not needed; Slope 7 can be a 5' grade to distance at -2.5:1 followed by a grade to surface at -2:1 that would take the place of (1))
6. Check the rest of the drawing to be sure no previously created gradings have disappeared.
   1. If the drawing has become corrupt, close without saving and start over using a clean copy of the backup.
   2. If everythong looks good:
      1. Purge, all; Audit, yes; -Purge, registered apps, *, no
      2. Save this working drawing.
      3. Save As using the original name to replace the backup copy.

This could also be done using corridors. You would probably need custom subassembly that worked backwards to create some auxilary points.

Good luck! 

---

 I end up making an subassembly following @ChrisRS's idea. It worked.