Learn how to modify "widening" parameters in Civil 3D, including refining the use of grip edits, opting for offset parameters, and choosing the right transition in and out. This resource explains how to select and modify alignments and optimize your workflow to suit your specific project needs.
Key Insights
- To refine the modification of widening parameters in Civil 3D, you can utilize the offset parameters option within the contextual ribbon bar, instead of relying solely on grip edits.
- There are multiple ways to add a widening to an existing offset alignment within Civil 3D, you can create a widening from the home alignment or use the add widening option in the offset parameters section. The key is to find the workflow that works best for you.
- When modifying widenings, it's important to carefully choose the transition in and out, transition length and taper ratio. These choices should be based on the need for enough room for cars to maneuver and for drivers to accelerate or decelerate smoothly.
Note: These materials offer prospective students a preview of how our classes are structured. Students enrolled in this course will receive access to the full set of materials, including video lectures, project-based assignments, and instructor feedback.
So in this video, we're going to go ahead and modify that widening that we created in the previous video. So to do that, what I'm going to go ahead and do is I'm going to select the alignment that we're working with.
And inside of here, what you can see is we have these grip edits for the widening that was created. We have, we can click this button here to get the widening grips. And then inside of here, we have these grips that we can modify that are associated with that widening.
Now you could go ahead and use these grips to modify your widening, but this is a very unrefined way to do it. So what we're going to go ahead and do is we're going to select that widening. And then up inside the contextual ribbon bar, what we're going to do is we're going to select offset parameters.
So you may have noticed next to offset parameters is add widening. That is another way to add a widening to an existing offset alignment. So instead of like we did before, where it was home alignment, create widening, you could have selected this offset alignment, then selected add widening.
Another option to add a widening is to select offset parameters and then select the button in here for add widening. So there's multiple ways, and this is for everything inside of Civil 3D. There are multiple ways to do the same action inside Civil 3D.
Learn Civil 3D
- Nationally accredited
- Create your own portfolio
- Free student software
- Learn at your convenience
- Authorized Autodesk training center
So what's important is to find the workflow that works best for you and utilize that workflow to its best potential. So my favorite way to deal with widenings is to work inside of this widening window. So from here, what we're going to go ahead and do is we're going to choose our transition in and choose our transition out.
So our transition out, I don't like the curve line curve for a transition out. I like to do a linear transition out because as somebody's accelerating, we want them to accelerate into the roadway and not have it be anything abrupt or curved or anything like that. We want to have them just have a standard merge.
So I'm going to go ahead and choose linear for my out, and then I'm going to go ahead and navigate over to my widening, and I'm going to choose a curve line curve. So just like a standard turn pocket, it's going to have a curve, a tangent section, and another curve. And so then we get to deal with how we're going to be transitioning.
We have the transition length. How far do we want to have this length go? And as we march our way through these sections, Civil 3D is going to highlight the section that we're working at. So this is our transition in.
If I went here and selected, this is our transition out. If I went here and selected, this is our widening section. So transition length for our turn pocket, I'm going to go ahead and put in 25.
And you can see this looks more like a standard opening for a turn pocket. So from here, you have your options for your curve one radius and your two radius. I'm going to go ahead and type in 15 and 15 and see how this looks.
So as I zoom in here, this looks good. Depending on how you want to orient your turn pocket, whatever your standards are for how you do that turn pocket, you may need to modify this. I'm comfortable with how this looks because we're not actually designing this for a set municipality.
This is just for our perfect world of creating this for a generic design. So what we're going to go ahead and do now is we're going to navigate over to our transition out. So what we have, once you've chosen linear, is we have something different from our curve line curve.
So every time you choose something, the parameters below are going to change. So curve, curve, reverse curve, you would have settings for the curve, curve, and the reverse curve. Linear is going to give you an option for your taper input type.
And then your curve reversing curve is going to give you your curve and your reversing curve radiuses. So from linear, you have two options by length and by taper ratio. I prefer taper ratio because it's something that I learned when I originally started in the transportation design industry.
So I want to have a taper ratio of one and five as I'm coming out of this. So I'm going to go ahead and go one and five and hit ENTER. And so what you'll notice here is that's one and five.
Now, now that I'm looking at that, that's actually a little too severe. So I'm going to actually change this to one and ten. That looks a little bit better.
So I like this one and ten change. So what we're going to go ahead and do now is we're going to modify our widening region. So from here, what we're going to go ahead and do is choose a new start station, choose a new end station.
So what that's going to do for us is we're going to be able to figure out where our intersection is and then pick a start station and pick an end station that makes sense for having enough room for cars to pull in and having enough length for somebody to accelerate. So what we can see here is that our intersection comes in somewhere around the one plus zero. It's actually ninety seven ish something in there because the one plus zero is right here.
So what we're going to go ahead and do for our purposes here is I'm going to change my start station. Let's go ahead and change it to 40. And so when I change that to 40, you'll notice that my widening moved all the way back here.
If for some reason 40 wasn't right, maybe we want to go with 30. I can just keep typing in numbers. So this is getting pretty close to the end.
This does look like a good amount of space for a car or two or three to queue up and make this turn in. So I'm going to go ahead and leave this start station as plus 30. And then let's say I wanted to have 200 feet of acceleration before we start tapering somebody into the main alignment.
So I know that this intersection happens somewhere around one plus zero. So 200 feet from there would be 100,200. That would be three plus zero.
So I'm going to go ahead and type in 300 and hit ENTER. And so 300 converts to three plus zero. This gives me the beginning of my taper in and then we have our taper into our main alignment here again.
So I'm going to go ahead and say I'm done with this and escape out so that we can see what our transition looks like. We have a turn pocket coming in and we have an acceleration lane coming out. Now you can easily get back into this again by selecting, going to offset parameters and modifying your choices.
You can also do your add widenings and your add automatic widenings. We're going to go ahead and save and then I'll meet you in the next video and we're going to start talking about profiles.
