Learn how to create an offset alignment within Civil 3D, along with the important considerations for naming, station range, and offset details. The tutorial also covers the application of these concepts to the specific task of creating an offset alignment that mimics the edge of a highway pavement.
Key Insights
- The first step in creating an offset alignment in Civil 3D is to select "create offset alignment" from the alignment drop-down menu. Afterward, the software prompts you to select an alignment or press the enter key to choose from a list of all alignments within Civil 3D.
- During the process, users can specify the alignment to offset from, the offset name template, and the offset distance. The naming template window provides property fields for the counter offset distance, parent alignment name side, and the incremental number format.
- For the station range, users have the option to create an offset alignment that does not match the start and end point of their alignment. The offset's direction (left or right) is determined by the direction in which the alignment is drawn. In this case, an 18-foot offset to the right side was created to mimic the highway's edge of pavement.
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So in this video, we're going to go ahead and create an offset alignment. So to do that, I'm going to navigate up to the alignment drop down.
I'm going to drop down and I'm going to select create offset alignment. So from here, we have been prompted by Civil 3D to select an alignment or press ENTER key to select from list. So I'm going to go ahead and instead of selecting the alignment, I'm going to hit ENTER.
And inside of here, you now have the options of all of the alignments that you have inside of Civil 3D. So I want to go ahead and create an offset alignment from our existing highway. We're going to be creating an offset alignment that mimics where the edge of pavement is.
So I'm going to go ahead and select okay. Now inside of the create offset alignment window, we have the options for the alignment to offset from. If for some reason you selected the wrong one, you could select the one that you actually wanted to use.
Then you have the options for what your offset name template is going to be. So you can type in a name here, or you can go with what Civil 3D auto prompts in here, which is parent alignment name side and offset distance. So that would be parent alignment, EX highway side.
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We're going to offset to the right side because that's where we're going to be doing some work on the highway. And then the offset distance, we're going to do an offset of 18 feet. So our name of our new alignment would be called X highway right 18.
You have the option for choosing a new name or editing the name template instead of typing it in yourself. And if you do that, then you have the naming template window, which gives you property fields. So next counter offset distance, parent alignment name side, and then you insert that down into the name.
And then you have the incremental number format. So what your number style is your starting number, your increment value, and that is for your counter, your next counter. So from here, I like the parent alignment name side offset distance.
So I'm going to go ahead and click. Okay. Now we have the station range.
If we wanted to create an alignment, an offset alignment that did not match the start and end point of our alignment, you could uncheck the box, choose your station, and then uncheck this box and choose your end station. I want to have this offset from the beginning of my alignment to the end of my alignment. So I'm going to go ahead and leave both these boxes checked.
I'm going to go ahead and change the number of offsets on the left to zero because I don't want to have any on the left hand side. And so left and right is an interesting concept inside of civil 3D and civil design. Um, the left and right is based on the direction that your alignment is drawn in.
So it's as you walk along this alignment, what would be left and what would be right. If we moved from this end to this end, left would be this side, right would be this side. So left is to the top, right is to the bottom.
We're going to be creating an offset alignment towards our development area, and no offset alignment away from our development area, because that offset, we don't, we do have some information on where the edge of the roadway is, but we're not going to be making modifications to that side of the road for our new development. So I've got a no on offset on the left and a one on offset on the right. So zero and one, it doesn't matter what my increment is on the left side, because I don't have any offsets that I'm going to do.
But like I said before, we're going to go ahead and do an 18 foot offset to the right. We're going to go with 18 for the offset. And then you have options for if you wanted to add a widening around curves, you can check this, and then you can specify based on certain standards.
I'm going to go ahead and add a widening later. So not as concerned with adding widenings right now. Same thing with creating offset profiles, you can create a profile for your offset based on certain parameters.
We don't have a profile for our current centerline alignment. So it doesn't make sense that we'd be creating a profile. We have nothing to base it off of.
We can't do that yet. We're going to go ahead and go back to the general tab. So inside of the general tab, we have the options for site.
Generally, your offset alignment is going to be cited to whatever the site is for your parent alignment. Then you have the options for the style. We're going to go ahead and select offset for our offset alignment.
We're going to leave it as C road for our alignment layer. And then we're going to go ahead and leave it as no labels for our land alignment label set. So I'm going to go ahead and click OK.
And what you'll notice inside of here is that civil 3D has now created a new alignment that is offset from our centerline alignment. And as you can see here, it's pretty good at hitting these curves here. Not so great at hitting these lines here.
Better as we get closer to this end. So it's a good approximation, but we're going to go ahead and move on from here. We're going to save.
And then in the next video, we'll talk about creating widenings.
