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Professional CAD/CAM tools built on Inventor and AutoCAD
Integrated BIM tools, including Revit, AutoCAD, and Civil 3D
Professional CAD/CAM tools built on Inventor and AutoCAD
Use several different methods to create rail alignments in Civil 3D.
Type:
Tutorial
Length:
10 min.
Transcript
00:00
In this video, we'll look at several different methods for creating rail alignments for either existing or proposed alignments.
00:11
We'll also take a look at some ways to create some very complex geometry to avoid conflicts or fouling points.
00:19
So, in the first example we have 3D Poly lines that were extracted from a point cloud.
00:24
So, in the Autodesk construction cloud, we can extract key features like rail lines or platform edge lines from the cloud,
00:31
and we can use those 3D lines in Civil 3D as a basis for our alignment.
00:36
We can also see that these lines are in the correct Geo reference location.
00:40
So, on the Home tab, we can choose alignments and pick Create Best Fit alignment.
00:46
With this option, we can choose between AutoCAD entities like Poly lines or blocks, COGO points, or in this case,
00:53
we'll actually choose feature lines.
00:55
We can use the selection tool to pick the left rail for the first line and the right rail as the second line.
01:01
We'll increase the maximum radius just to be sure that we are including some of the larger curves that may exist on this alignment.
01:09
We can also adjust the spiral to curve value here, and this is a value that we can revise if we need to adjust our results.
01:16
We have the option to match tangents and spirals.
01:19
This option tends to make the alignment a lot less symmetrical.
01:23
For the other items, we'll leave them as default. We can also adjust the weeding options here,
01:28
and we can also control the maximum angle or distance, but we'll leave these off for now as well.
01:34
Once we select OK, we'll see a regression graph that will show the location of the solved alignment.
01:40
We can expect that to review the outcomes.
01:44
Once we close the window, the alignment will display.
01:47
And keep in mind once the alignment is set, we can adjust the values and the cardinal points if we need to
01:52
and can see some of the values or the links might need to be adjusted for a better fit.
01:57
And some of the things we can review and adjust as needed in the geometry editor.
02:02
In this example, we can select the alignment and go to the alignment properties.
02:06
Since we created this as a best fit alignment, we'll change this to a rail alignment.
02:11
In the design criteria tab, we can add some speed values and determine the specific criteria for our project.
02:19
And here we'll just use the default metric rail standards.
02:22
Now let's create an alignment from COGO points or survey points.
02:27
So here we want to start on the rail tab.
02:29
We can identify our alignment properties and include the name, stationing, and design criteria.
02:37
So, with the geometry editor toolbar, we can create individual elements of our alignments like the tangents and the curves.
02:45
So, let's start with the first tangent.
02:47
In the tangent drop-down, we can pick from a few options.
02:51
We'll pick the fixed line best fit.
02:53
We have some options here to choose from, but let's select COGO points.
02:57
You can see in general where the tangent is located.
03:00
But even if we choose some points that are outside of that tangent, we can edit those in the window.
03:06
So, when we pick the points, we can see our regression graph.
03:09
So, if we need to exclude some of those points from the tangent section, we can do this,
03:14
and the graph will update to show the solved tangent section.
03:19
Once we get that to where it looks accurate, we can close the window.
03:23
Once that window is closed, the tangent section will appear.
03:27
And since this alignment is a freight line, we want to define this by chord definition.
03:32
So, let's pick the alignment and go to the alignment properties.
03:37
Under the station control tab, we can select chord definition.
03:41
We could also add our design speed to our alignment and then those labels will appear for the alignment.
03:49
In our case, the station is exactly going the wrong direction.
03:53
So, if this is the case, we select the alignment and pick the drop down from the modify menu and choose reverse direction.
04:01
So, once we select the prompt, we can see that the alignment is revised.
04:05
Now let's pick the curve section.
04:07
We'll do something similar by choosing the curve drop-down.
04:12
And for clarification, a fixed curve will be based on certain elements, and here those will be based on COGO points.
04:18
The floating curves are fixed on one end to another element of the alignment,
04:23
and free curves are calculated between two existing elements.
04:27
So, we'll choose the fixed curve for best fit, and we'll go through the similar workflow based on the COGO points,
04:33
pick the points that look like they're in the body of the curve.
04:36
Similarly, we can exclude points that are outside, based on our regression analysis.
04:42
And now we have a separate curve from the tangent.
04:45
These are both part of the same alignment even though they don't connect.
04:49
And we'll do the same thing all the way up our alignment for the rest of the tangents and the curves.
04:55
Now we want to connect these tangents and curves with spirals, so we'll pick the free spiral from the spiral drop-down list.
05:03
And in our case, it actually tells us that there's no solution found when we pick the two options.
05:07
We may need to actually reverse the direction of our curve element.
05:13
So, we can pick the reverse direction tool in our toolbar and pick the curve.
05:19
Now when we create a connecting spiral, we can see the results are connecting the two elements.
05:24
We can do the same thing all the way up the alignment.
05:27
So, this is another way that we can create existing alignments based on field data or point cloud data.
05:35
And all of our curve elements are identified when we review the alignment in this window.
05:41
So let's look at creating proposed alignment by laying out PI locations.
05:46
So we've identified the PI locations in this example with circles, but we could do this a number of different ways.
05:52
We could use construction lines or a dummy layout.
05:54
In the rail tab, we'll pick the creation tools and populate the information for our alignment.
06:00
We'll pick the PI tool and we can go through the alignment and snap to all those PI locations.
06:10
We'll do the same thing for the southbound track.
06:17
Now we want to create spiralized curves for each PI location.
06:21
One item of note, we can choose from several different spiral types, depending on our project requirement.
06:27
And we can change that in the PI drop-down by selecting Spiral.
06:31
For this option, we'll just stay with Clothoid.
06:33
To make the spiral curves, we can pick the drop-down menu here, and we'll pick a free curve.
06:39
Again, a free curve is calculated between.
06:41
If we're not sure which method we want to choose,
06:43
if we look at the parentheses, we can determine what factors we're basing the curve on.
06:48
So once we pick that option, we'll pick the first, then the second element, then input the curve radius and the spiral lengths.
06:55
These values should be based on our design speed and our design criteria, and if they're outside of that,
07:00
will receive a warning notice on those curves or spirals.
07:05
We'll do this both for the northbound and the southbound alignment.
07:10
Looking at some more complex examples, let's take a look at some other methods for laying out some rail alignments.
07:16
We can create alignments from objects, but since we can't realistically draw a spiral, we'll end up getting geometry that we may not like.
07:26
So we'll pick the alignment from objects, define the direction of our stationing, then input some alignment parameters.
07:34
If, when we create the alignment, we don't see any labels, we can add those by picking the alignment and choosing Edit Alignment Labels
07:41
with the right-click menu.
07:44
Here we can add cardinal points, stationing, or other labels that we might need.
07:49
Once those display, we can see we have a number of curves representing the spiral.
07:54
So if we use the grips and edit the alignment, the other elements actually don't update with the grips.
08:01
If we need to create an alignment from objects, it's best to redefine the curve geometry by using edit alignment tools
08:09
and then deleting the curve and recreating it with spirals.
08:17
In the next example, we want to take a look at an existing alignment where we may need to avoid conflicts by creating a compound curve,
08:25
or we may want to see what to do if we have multiple items that we need to avoid.
08:30
So here, we'll remove the existing curve and show just the tangent in and out.
08:35
To create a compound curve, we can pick the spiralized curve drop-down,
08:40
and then select compound spiral curve, spiral curve, spiral between two tangents.
08:46
Once we input the parameters, we'll see a preview of the solved alignment.
08:52
We could also base the curvature on a through point, a begin point, or an end point.
08:56
If we don't see that preview solution, we may need to adjust our curve parameters.
09:01
Next, we've identified several conflict points with their clearance distance.
09:07
In this case, we need to base our alignment on those clearance envelopes.
09:12
So we'll lay out this alignment a segment at a time to make sure that we optimize our geometry.
09:17
So we'll pick the floating curve with a spiral from a point with a radius and a through point.
09:23
So we'll pick our tangent, provide the curve and spiral parameters, then we can pick the tangent point based on that clearance envelope.
09:33
We can do the same thing for the next curve, the same function, but with different parameters.
09:38
Then to end the curve, we can add a floating line with a spiral.
09:43
However, in our case this doesn't match our required tangent out of this curve.
09:49
So to make sure that we close this curve on the correct tangent, we'll create a tangent, then add a close out spiral to complete the curve.
09:58
We'll add a free curve between two elements.
10:02
And the length will be calculated automatically.
10:05
And again, if we need to get in and revise or edit the alignment parameters, we can do that with grips, or in the geometry table.
Video transcript
00:00
In this video, we'll look at several different methods for creating rail alignments for either existing or proposed alignments.
00:11
We'll also take a look at some ways to create some very complex geometry to avoid conflicts or fouling points.
00:19
So, in the first example we have 3D Poly lines that were extracted from a point cloud.
00:24
So, in the Autodesk construction cloud, we can extract key features like rail lines or platform edge lines from the cloud,
00:31
and we can use those 3D lines in Civil 3D as a basis for our alignment.
00:36
We can also see that these lines are in the correct Geo reference location.
00:40
So, on the Home tab, we can choose alignments and pick Create Best Fit alignment.
00:46
With this option, we can choose between AutoCAD entities like Poly lines or blocks, COGO points, or in this case,
00:53
we'll actually choose feature lines.
00:55
We can use the selection tool to pick the left rail for the first line and the right rail as the second line.
01:01
We'll increase the maximum radius just to be sure that we are including some of the larger curves that may exist on this alignment.
01:09
We can also adjust the spiral to curve value here, and this is a value that we can revise if we need to adjust our results.
01:16
We have the option to match tangents and spirals.
01:19
This option tends to make the alignment a lot less symmetrical.
01:23
For the other items, we'll leave them as default. We can also adjust the weeding options here,
01:28
and we can also control the maximum angle or distance, but we'll leave these off for now as well.
01:34
Once we select OK, we'll see a regression graph that will show the location of the solved alignment.
01:40
We can expect that to review the outcomes.
01:44
Once we close the window, the alignment will display.
01:47
And keep in mind once the alignment is set, we can adjust the values and the cardinal points if we need to
01:52
and can see some of the values or the links might need to be adjusted for a better fit.
01:57
And some of the things we can review and adjust as needed in the geometry editor.
02:02
In this example, we can select the alignment and go to the alignment properties.
02:06
Since we created this as a best fit alignment, we'll change this to a rail alignment.
02:11
In the design criteria tab, we can add some speed values and determine the specific criteria for our project.
02:19
And here we'll just use the default metric rail standards.
02:22
Now let's create an alignment from COGO points or survey points.
02:27
So here we want to start on the rail tab.
02:29
We can identify our alignment properties and include the name, stationing, and design criteria.
02:37
So, with the geometry editor toolbar, we can create individual elements of our alignments like the tangents and the curves.
02:45
So, let's start with the first tangent.
02:47
In the tangent drop-down, we can pick from a few options.
02:51
We'll pick the fixed line best fit.
02:53
We have some options here to choose from, but let's select COGO points.
02:57
You can see in general where the tangent is located.
03:00
But even if we choose some points that are outside of that tangent, we can edit those in the window.
03:06
So, when we pick the points, we can see our regression graph.
03:09
So, if we need to exclude some of those points from the tangent section, we can do this,
03:14
and the graph will update to show the solved tangent section.
03:19
Once we get that to where it looks accurate, we can close the window.
03:23
Once that window is closed, the tangent section will appear.
03:27
And since this alignment is a freight line, we want to define this by chord definition.
03:32
So, let's pick the alignment and go to the alignment properties.
03:37
Under the station control tab, we can select chord definition.
03:41
We could also add our design speed to our alignment and then those labels will appear for the alignment.
03:49
In our case, the station is exactly going the wrong direction.
03:53
So, if this is the case, we select the alignment and pick the drop down from the modify menu and choose reverse direction.
04:01
So, once we select the prompt, we can see that the alignment is revised.
04:05
Now let's pick the curve section.
04:07
We'll do something similar by choosing the curve drop-down.
04:12
And for clarification, a fixed curve will be based on certain elements, and here those will be based on COGO points.
04:18
The floating curves are fixed on one end to another element of the alignment,
04:23
and free curves are calculated between two existing elements.
04:27
So, we'll choose the fixed curve for best fit, and we'll go through the similar workflow based on the COGO points,
04:33
pick the points that look like they're in the body of the curve.
04:36
Similarly, we can exclude points that are outside, based on our regression analysis.
04:42
And now we have a separate curve from the tangent.
04:45
These are both part of the same alignment even though they don't connect.
04:49
And we'll do the same thing all the way up our alignment for the rest of the tangents and the curves.
04:55
Now we want to connect these tangents and curves with spirals, so we'll pick the free spiral from the spiral drop-down list.
05:03
And in our case, it actually tells us that there's no solution found when we pick the two options.
05:07
We may need to actually reverse the direction of our curve element.
05:13
So, we can pick the reverse direction tool in our toolbar and pick the curve.
05:19
Now when we create a connecting spiral, we can see the results are connecting the two elements.
05:24
We can do the same thing all the way up the alignment.
05:27
So, this is another way that we can create existing alignments based on field data or point cloud data.
05:35
And all of our curve elements are identified when we review the alignment in this window.
05:41
So let's look at creating proposed alignment by laying out PI locations.
05:46
So we've identified the PI locations in this example with circles, but we could do this a number of different ways.
05:52
We could use construction lines or a dummy layout.
05:54
In the rail tab, we'll pick the creation tools and populate the information for our alignment.
06:00
We'll pick the PI tool and we can go through the alignment and snap to all those PI locations.
06:10
We'll do the same thing for the southbound track.
06:17
Now we want to create spiralized curves for each PI location.
06:21
One item of note, we can choose from several different spiral types, depending on our project requirement.
06:27
And we can change that in the PI drop-down by selecting Spiral.
06:31
For this option, we'll just stay with Clothoid.
06:33
To make the spiral curves, we can pick the drop-down menu here, and we'll pick a free curve.
06:39
Again, a free curve is calculated between.
06:41
If we're not sure which method we want to choose,
06:43
if we look at the parentheses, we can determine what factors we're basing the curve on.
06:48
So once we pick that option, we'll pick the first, then the second element, then input the curve radius and the spiral lengths.
06:55
These values should be based on our design speed and our design criteria, and if they're outside of that,
07:00
will receive a warning notice on those curves or spirals.
07:05
We'll do this both for the northbound and the southbound alignment.
07:10
Looking at some more complex examples, let's take a look at some other methods for laying out some rail alignments.
07:16
We can create alignments from objects, but since we can't realistically draw a spiral, we'll end up getting geometry that we may not like.
07:26
So we'll pick the alignment from objects, define the direction of our stationing, then input some alignment parameters.
07:34
If, when we create the alignment, we don't see any labels, we can add those by picking the alignment and choosing Edit Alignment Labels
07:41
with the right-click menu.
07:44
Here we can add cardinal points, stationing, or other labels that we might need.
07:49
Once those display, we can see we have a number of curves representing the spiral.
07:54
So if we use the grips and edit the alignment, the other elements actually don't update with the grips.
08:01
If we need to create an alignment from objects, it's best to redefine the curve geometry by using edit alignment tools
08:09
and then deleting the curve and recreating it with spirals.
08:17
In the next example, we want to take a look at an existing alignment where we may need to avoid conflicts by creating a compound curve,
08:25
or we may want to see what to do if we have multiple items that we need to avoid.
08:30
So here, we'll remove the existing curve and show just the tangent in and out.
08:35
To create a compound curve, we can pick the spiralized curve drop-down,
08:40
and then select compound spiral curve, spiral curve, spiral between two tangents.
08:46
Once we input the parameters, we'll see a preview of the solved alignment.
08:52
We could also base the curvature on a through point, a begin point, or an end point.
08:56
If we don't see that preview solution, we may need to adjust our curve parameters.
09:01
Next, we've identified several conflict points with their clearance distance.
09:07
In this case, we need to base our alignment on those clearance envelopes.
09:12
So we'll lay out this alignment a segment at a time to make sure that we optimize our geometry.
09:17
So we'll pick the floating curve with a spiral from a point with a radius and a through point.
09:23
So we'll pick our tangent, provide the curve and spiral parameters, then we can pick the tangent point based on that clearance envelope.
09:33
We can do the same thing for the next curve, the same function, but with different parameters.
09:38
Then to end the curve, we can add a floating line with a spiral.
09:43
However, in our case this doesn't match our required tangent out of this curve.
09:49
So to make sure that we close this curve on the correct tangent, we'll create a tangent, then add a close out spiral to complete the curve.
09:58
We'll add a free curve between two elements.
10:02
And the length will be calculated automatically.
10:05
And again, if we need to get in and revise or edit the alignment parameters, we can do that with grips, or in the geometry table.
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