Learn how to effectively use grading criteria in Civil 3D by creating a desilting basin for a community. The article dives into the various steps of creating a feature line, setting elevations, defining grading criteria and finally creating the basin.
Key Insights
- The article provides a detailed process of creating a desilting basin in Civil 3D, starting with the creation of a feature line at the top of a canyon.
- It explains the importance of setting correct elevations for the feature line and how to define the grading criteria for the desilting basin, emphasizing on a 10 feet deep basin with three to one side slopes.
- Using the grading creation tools in Civil 3D, the author demonstrates how to create the basin, infill it and verify the dimensions using the object viewer in the software.
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So in this video, we're going to go ahead and start working with some of the other Grading Criteria that we have inside of Civil 3D. We're going to go ahead and move away from dealing with our grading pads for our sites, and we're going to go ahead and create a desilting basin for the entire community.
In order to do that, we're going to go ahead and place it somewhere in this region here, kind of at the top of this canyon right here. So I'm going to go ahead and zoom in here. I'm going to start by creating a Feature Line.
So I'm going to go ahead and type in PL because I want to create a polyline that's going to be associated with this Feature Line. I'm going to go ahead and draw in my Feature Line or my polyline for my Feature Line somewhere running along the back of these lots. I'm going to come across over to here somewhere.
I'm going to come back up into this corner over here, and then I'm going to close off my shape. I'm going to go ahead and do a fillet command. I'm going to fillet with a radius of 10 feet.
Let's go ahead and actually go with 30 feet. So I'm going to go ahead and hit ENTER for that, and then I am going to type M for multiple, and then I'm going to select my polyline. Actually, instead of doing multiple, I'm going to go ahead and go with P for polyline.
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I'm going to go ahead and select my polyline so that I've filleted off all the corners. I'm going to go ahead and hit Escape. I'm going to select this line.
I'm going to go ahead and go to Feature Line, Create Feature Line from Object. I'm going to go ahead and leave it on my Dev Main site. I'm going to go ahead and call this basin, and I'm actually going to define this as Basin Top.
This is going to be the top of our desilting basin. So I'm going to leave it as a Grading Design style. I'm going to go ahead and leave it as C Top of Feet.
I am going to erase existing entities. I am not going to assign elevations. I'm going to go ahead and click OK.
So Civil 3D now has created this Feature Line for me. I'm going to go ahead and set these elevations. I'm going to set this so that it is set slightly below this elevation here, and so we know this elevation based on this label for our contours is 190.
So I'm going to set this two feet below. So I'm going to set it at 188. I'm going to go ahead and go to my Elevation Editor.
I'm going to go to my increment. I'm going to change this to 188, and then I'm going to go ahead and raise that Feature Line up to 188 because it was sitting at zero. I'm going to go ahead and check this off.
I'm going to hit Escape, and now we're going to go into creating the first Grading Criteria for this desilting basin. I'm going to go ahead and go to my Grading drop-down. I'm going to select Grading Creation tools, and then I'm going to march through selecting the correct criteria for the Grading Group or Grading Object that I'm dealing with.
So I'm going to go ahead and make sure that I have my Grading Group set to Dev Main, Dev Main Grad. I'm okay with this being associated with the rest of this Grading Group over here, so I'm going to go ahead and click OK. Now, if we wanted to, we could have created our own Grading Group, our own site, and everything else for this specific Grading Object, but I'm more than fine with it being associated with the Grading Objects over here.
We're going to go ahead and set our Surface because we will be doing a Surface target eventually, but for now, I want to go ahead and set it as 203, and we'll use it later. I'm going to go ahead and check my Surface or my layers. I'm going to go make sure it's C-TOBO-GRAD, click OK.
I'm going to go ahead and make sure that I'm still using my DevGrad Criteria Set. Now, the other way to check that would be to drop down and check which criteria I have, and then that would give me the indication on whether or not I'm in the correct Criteria Set. So from here, we're going to go ahead and go Relative Elevation – Slope.
We want to do a 3:1 side slope on this. So I'm going to go ahead and make sure that we're targeting a Slope and then a Relative Elevation. I want to make sure it's a 10-foot-deep desilting basin.
So I'm going to click here. I'm going to go into this method here. I am actually going to go ahead and modify this so that we can go ahead and just use what Civil 3D prompts us to rather than doing it as we're making the Grading Object.
So I'm going to go ahead and select Edit Current Selection. I'm going to go here and choose 10 as my Relative Elevation, and I'm going to go ahead and modify this to 3:1. I'm going to click Apply and click OK.
And so what we're going to see is that it updates these to 10 and 3:1. So from here—well, first things first—I made an error. Our Relative Elevation should not be 10 because we're trying to create a basin.
If I did an elevation of 10, it would raise up by 10 feet at a 3:1 slope. I don't want to raise up. I want to go down.
So I'm going to go ahead and edit this again. I'm going to go ahead and go to 10. I'm going to type in -10.
So I'm going to go ahead and click Apply and click OK. Now we've got a -10.
Now that I have my Grading Criteria set up, I'm going to go ahead and drop down and select Create Grading. Civil 3D is going to prompt me to select a Feature. I'm going to pick this Feature Line here.
It's going to ask me to select a Grading side. I'm going to pick into the inside. It's going to ask me to apply to the entire length.
I am going to say yes. I'm going to choose -10. I am going to leave it as 3:1. Now that I've done that, Civil 3D has created this depression here.
I'm going to go ahead and drop down and create an infill for this. I'm going to select Create Infill. I'm going to go ahead and pick on the inside.
And now I'm going to go ahead and Escape out. I'm going to close this off and then I'm going to check this Grading Object. I'm selecting the two diamonds.
I'm going to go to Object Viewer. I'm going to go ahead and bring my Object Viewer over, expand this out, rotate it out. And what you'll see here is we have a desilting basin that is 10 feet deep with 3:1 side slopes.
I'm going to go ahead and close this. I'm going to save it. And then I'll meet you in the next video where I'll finish out this desilting basin.
