Create sample lines

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In this video, we're going to kick off our discussion of roadway cross sections.

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When we create roadway cross sections inside Civil 3D, the first object that we need to create is sample lines.

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Inside of Civil 3D, sample lines are the backbone of creating any sections,

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that we're going to use to display what our roadway looks like inside of Civil 3D.

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So in order to get to a sample line creation window, we're going to navigate to the Home tab of the ribbon bar.

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We're going to navigate over to the Section Views section, and we're going to go to the Sample Lines option.

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So I'm going to pick sample lines, and Civil 3D prompts me to select an alignment or press enter to select from list.

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I'm going to select "Enter" to select from the list.

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And I'm going to select my Dev-Align alignment.

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So I'm going to go ahead and click "OK".

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And then from here, we get into the Create Sample Line Group.

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A sample line group is just a list of sample lines and then what information we're sampling from.

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So what I'm going to go ahead and do is I'm going to name my sample line group, Dev-Xsec.

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And then I'm going to leave it as a counter so that if we create more, this will be the first one and will move upwards from there.

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I'm going to go ahead and leave my sample and style as road sampling.

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But just like any other object inside Civil 3D, you can edit or create new ones.

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The sample line options are pretty simple, all you have are lines and vertices.

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Then in Model space, same thing, lines and vertices.

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And then your Summary tab and what it's called.

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So, not a lot of customization there.

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So I'm going to go ahead and leave it as road sample line.

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Then we have our sample line label styles.

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Again, just like all the other label styles that we've talked about,

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it's going to place a label on your sample lines so that you know which sample line you're looking at.

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And then we go down into the data sources.

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So when you do a sample line, you're effectively cutting a miniature profile across that sample line.

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And so that miniature profile that's cut across that sample line samples from certain surfaces or corridors.

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And so in our first sample line set that we're going to create, we're going to go ahead and just sample from our EG surface.

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So I'm going to go ahead and unselect all of the other options.

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And then later, what we can do is we can add some information back depending on what we want to have to be shown in our cross section.

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So once you've done all of this, we're going to go ahead and click "OK".

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And now we have the sample line tool to work with.

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So the sample line tool has the options of what we're going to call our sample line, each individual sample line,

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what alignment we're based off of, which we already selected as our Dev-Align, what our sample line group is.

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And then we can create a different sample line group or edit the current group that we have, delete the current group.

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We can pick a group from the drawing.

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We can edit our swath widths, which we will talk about when we create our sample lines.

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And then we can sample more sources.

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We can also sample more sources later on using a different method.

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So we're going to go ahead and move on to the next option, which is how to actually create our sample lines.

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So when you create a sample line, you have five options here.

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You can create by a range of stations, which is what we're going to go ahead and do.

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Then you can add a specific station, so you can pick on the screen at what station you want to create a sample line.

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Then you can choose from corridor stations.

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So each station that we have placed a corridor cross-section, they will also place a sample line at.

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You can also pick points on a screen, so you can basically draw a line on the screen using points,

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or you can select an existing polyline to turn into a sample line.

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So we're going to go ahead and go with by range of stations.

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And we get the create sample lines by range of stations window.

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So moving down from here, we have our station range.

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Do we want to start it from our alignment start?

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For this, I'm going to go ahead and select false because we want to pick a new start station.

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So I'm picking the green box and then I'm going to go navigate down to the beginning of my alignment.

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The reason we don't want to create a cross-section from the beginning of our alignment is that we don't actually have any cross-sections in this area.

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So what I'm going to do is I'm going to pick this beginning of our corridor as the beginning of our alignment to start creating sections from.

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Then I'm going to go ahead and go to alignment end and I'm going to also select that as false,

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because our alignment end is in the middle of our cul-de-sac.

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So I'm going to go ahead and pick the green box again to be able to pick on screen our endpoint.

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I am going to navigate to the cul-de-sac.

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And I'm going to select the end of an arc right here,

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which is the end of our tangential section before we open up into our corridor, or into our cul-de-sac.

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So from here, then we have the option for swath widths.

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So what swath widths are is you have a left and a right, it's basically an offset.

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How far do you want to offset from the centerline to create your sample line?

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So if you want your sample line to be 30 feet to the left of your centerline and 30 feet to the right of your centerline,

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then you would adjust your widths.

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So if you want to snap to a specific alignment, if you had a swath width alignment that you wanted to sample to,

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then you could go ahead and set this as true.

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I don't have those so I'm going to go ahead and go with false.

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But I am going to change my swath width because our roadway is only about 30 feet in half, so it's 60 feet wide.

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I'm going to go ahead and set my swath width on both sides as 35.

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So I'm moving from left to right changing both from 50 to 35.

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And then we move on to how often we want to sample.

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You can use sampling increments, true or false, then increment relative to, you can choose an absolute station or your station range start.

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I don't want to have my sampling relative to my station range start because I'm starting my station at 29.11.

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I don't want everything to have a 0.11 on the end.

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So I am going to go with an absolute station and I'm going to change all of my increments from 50 to 25.

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So I'm moving in here, changing everything to 25.

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And then moving down, you can have additional sampling locations.

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So at range start, at range end, horizontal geometry points, so like a beginning of a curve or end of a curve, and then superelevation criticals.

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If we had set our superelevations to change based on our radiuses in a design setting,

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then it would basically put a cross-section at the critical point of your superelevation diagrams.

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So we're going to go ahead and leave these all as false and we're going to go ahead and click "OK".

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And so when would we do that, it doesn't appear like anything happened because nothing showed up in the command line.

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And we're now in another command, which is specify station along baseline because we're now in the at station command.

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But if you go ahead and hit "Escape" twice, what you're going to see is that we now have these blue lines that are running along our corridor.

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And at each one of them, it has a station equation that are 25 feet apart.

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And so these are our sample lines that we just created.