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Lay out the alignment by drawing individual entities and joining them up. Constrain, edit, and delete entities at any time.
Type:
Tutorial
Length:
8 min.
Transcript
00:03
We can convert autocad entities into an alignment.
00:07
But there are times when we don't have a full alignment in a drawing to convert,
00:11
sometimes we just want to lay out the alignment freely
00:14
in the model using background C ad entities to guide us
00:19
the alignment layout tools allow us to create an
00:21
alignment by drawing individual entities and joining them up.
00:26
We can control how they are constrained
00:28
and we can edit add and delete entities at any time.
00:34
Using the layout toolbar,
00:35
we can create an alignment by picking intersection points,
00:40
curves can be added automatically
00:42
at each intersection point.
00:45
We can add an intersection point,
00:49
delete an intersection point
00:53
and we can break apart an intersection point.
00:57
When we break the intersection point apart, we have two independent tangents
01:02
which we can then move individually.
01:05
We can use the delete button
01:07
to delete any of the entities from our alignment.
01:12
We can also create an alignment
01:13
by laying out individual entities such as lines and curves
01:18
on the toolbar. We have a button for lines,
01:21
curves,
01:23
floating lines with spirals,
01:25
curves with spirals and compound lines and curves with spirals.
01:30
Individual entities are divided between fixed floating and free
01:36
fixed curve. For example
01:38
is one that is fixed by the points. You pick.
01:41
When you add a fixed entity,
01:43
it will constrain other entities that you attach to it.
01:48
Floating entity is one that's attached at one end to another entity.
01:52
It floats from it
01:54
for this floating line.
01:56
Notice that the curve stays fixed in place
01:58
and the tangent line moves and is constrained
02:01
and remains tangential to the curve.
02:04
If I add another fixed line,
02:06
then we can add a free curve between these
02:09
a free entity is one that is attached at both ends
02:12
to other entities and is free to move when they move.
02:17
When you add a free curve, you need to choose the included angle.
02:20
If we choose greater than 180 then we get a curve that loops around like this.
02:26
If I choose less than 180
02:28
then the curve will be the shortest curve between the two tangents
02:35
on the alignment layout toolbar.
02:37
We can use the alignment grid view to review
02:39
the tangy constraints that we applied to our entities.
02:43
We can edit the constraints in the grid view
02:46
and change them
02:48
fixed entities. For example, can be changed to floating or free entities.
02:54
We can look at the parameters of individual entities using the sub entity editor
02:59
and review or edit them.
03:02
We use the select sub entity button to switch between entities.
03:07
We can add ORD
03:08
CD lines or acs to our alignment.
03:11
If I draw an arc in the opposite direction to the alignment and then add it.
03:14
When I try to join this up with a free straight,
03:17
you'll notice the application reports. No solution is found.
03:21
If I reverse the entity first using this button,
03:25
then the arc now goes in the same direction as the alignment
03:28
and I can join it up with a free line.
03:31
Now we'll lay out some alignments in our model.
03:35
First, we need to set the data shortcut project for this model.
03:39
Right? Click on the data shortcuts folder in prospector
03:42
and set the data shortcut project folder.
03:45
Make sure the folder is set to Iowa City 0403,
03:50
expand the surfaces collection under data shortcuts,
03:54
right? Click on existing ground and choose create reference.
03:57
This will bring the surface into our model as a reference,
04:01
change the surface style to contours 2 ft and 10 ft.
04:05
It's a good idea to be able to see the surface when you design your alignments
04:09
to ensure your alignment is placed sensibly in relation to the terrain
04:15
from the home ribbon, choose alignment.
04:18
Then alignment creation tools
04:22
set the alignment name
04:23
to mcallister boulevard.
04:28
We'll use the layout alignment style which has different
04:31
colors for lines and curves and is ideal for designing
04:37
in the design criteria. Turn on criteria based design,
04:42
accept the default design criteria file
04:45
and set the design check set to collector.
04:50
We're going to use a fixed line to create fixed
04:53
tangents where the yellow lines are drawn in the model.
04:56
From the tool bar
04:58
under the lines, button
04:60
choose fixed line two points
05:04
using an end point snap crate lines from the
05:07
start and end of each yellow line in the drawing
05:10
zoom and pan as necessary
05:12
and press enter. When all of the lines have been created
05:21
in the model between the first two tangents,
05:24
there are a series of autocad points.
05:28
These denote positions where our curve can pass through.
05:32
We use a free curve best fit
05:35
to find the best curve that matches these points.
05:39
Pick the end of the first tangent and then the start of the second tangent
05:45
in the best fit dialogue,
05:46
select from AUTOCAD points,
05:51
select each point in turn
05:53
and then press enter
05:57
a regression data table will be displayed
05:59
which shows information about the best fit curve
06:02
and the separation between the curve and depict points.
06:07
You can see the offset on line four is rather large.
06:10
So we can exclude this point from the selection.
06:14
The curve will be recalculated,
06:16
click the save button, then dismiss the dialogue.
06:20
The curve is now placed on the alignment
06:24
for the next curve. Choose free curve filet
06:27
between two entities radius,
06:31
pick the incoming tangent. Then the outgoing tangent
06:35
and press enter to accept less than 180. For the angle
06:39
on the command line, the radius is defaulting to 1500 ft.
06:44
The minimum required by the design criteria. F
06:48
we'll ignore this and type in 1000 for the radius.
06:52
Now place the last curve
06:54
using the same options
06:57
youll need to zoom in to pick the end of the first tangent.
07:01
You will see that when we place the last curve,
07:04
the alignment is now fully labeled.
07:06
This is because all of the entities are now joined up
07:09
and the alignment is complete.
07:12
Close the layout tool bar.
07:15
Now we'll create the Sycamore Heights alignment,
07:18
open the alignment, creation tools
07:20
and rename the alignment to sycamore heights.
07:25
In the design criteria
07:26
slit use criteria based design,
07:30
make sure the design criteria file is not selected,
07:33
set the design check set to subdivision.
07:37
This time, we will lay out the alignment using intersection points
07:41
from the intersection points, pull down choose curve and spiral settings,
07:47
set the default curve radius to 140 ft.
07:51
We won't be using any spiral curves,
07:54
go back to the intersection points button
07:56
and choose tangent to tangent with curves,
08:00
turn on your center point,
08:01
object snaps and then pick the marker circles in the drawing.
08:05
In turn
08:06
where we want to place the intersection points,
08:10
curves are drawn automatically
08:12
at each intersection point
08:13
using the default radius. We've set
08:18
weve now laid out the alignments.
Video transcript
00:03
We can convert autocad entities into an alignment.
00:07
But there are times when we don't have a full alignment in a drawing to convert,
00:11
sometimes we just want to lay out the alignment freely
00:14
in the model using background C ad entities to guide us
00:19
the alignment layout tools allow us to create an
00:21
alignment by drawing individual entities and joining them up.
00:26
We can control how they are constrained
00:28
and we can edit add and delete entities at any time.
00:34
Using the layout toolbar,
00:35
we can create an alignment by picking intersection points,
00:40
curves can be added automatically
00:42
at each intersection point.
00:45
We can add an intersection point,
00:49
delete an intersection point
00:53
and we can break apart an intersection point.
00:57
When we break the intersection point apart, we have two independent tangents
01:02
which we can then move individually.
01:05
We can use the delete button
01:07
to delete any of the entities from our alignment.
01:12
We can also create an alignment
01:13
by laying out individual entities such as lines and curves
01:18
on the toolbar. We have a button for lines,
01:21
curves,
01:23
floating lines with spirals,
01:25
curves with spirals and compound lines and curves with spirals.
01:30
Individual entities are divided between fixed floating and free
01:36
fixed curve. For example
01:38
is one that is fixed by the points. You pick.
01:41
When you add a fixed entity,
01:43
it will constrain other entities that you attach to it.
01:48
Floating entity is one that's attached at one end to another entity.
01:52
It floats from it
01:54
for this floating line.
01:56
Notice that the curve stays fixed in place
01:58
and the tangent line moves and is constrained
02:01
and remains tangential to the curve.
02:04
If I add another fixed line,
02:06
then we can add a free curve between these
02:09
a free entity is one that is attached at both ends
02:12
to other entities and is free to move when they move.
02:17
When you add a free curve, you need to choose the included angle.
02:20
If we choose greater than 180 then we get a curve that loops around like this.
02:26
If I choose less than 180
02:28
then the curve will be the shortest curve between the two tangents
02:35
on the alignment layout toolbar.
02:37
We can use the alignment grid view to review
02:39
the tangy constraints that we applied to our entities.
02:43
We can edit the constraints in the grid view
02:46
and change them
02:48
fixed entities. For example, can be changed to floating or free entities.
02:54
We can look at the parameters of individual entities using the sub entity editor
02:59
and review or edit them.
03:02
We use the select sub entity button to switch between entities.
03:07
We can add ORD
03:08
CD lines or acs to our alignment.
03:11
If I draw an arc in the opposite direction to the alignment and then add it.
03:14
When I try to join this up with a free straight,
03:17
you'll notice the application reports. No solution is found.
03:21
If I reverse the entity first using this button,
03:25
then the arc now goes in the same direction as the alignment
03:28
and I can join it up with a free line.
03:31
Now we'll lay out some alignments in our model.
03:35
First, we need to set the data shortcut project for this model.
03:39
Right? Click on the data shortcuts folder in prospector
03:42
and set the data shortcut project folder.
03:45
Make sure the folder is set to Iowa City 0403,
03:50
expand the surfaces collection under data shortcuts,
03:54
right? Click on existing ground and choose create reference.
03:57
This will bring the surface into our model as a reference,
04:01
change the surface style to contours 2 ft and 10 ft.
04:05
It's a good idea to be able to see the surface when you design your alignments
04:09
to ensure your alignment is placed sensibly in relation to the terrain
04:15
from the home ribbon, choose alignment.
04:18
Then alignment creation tools
04:22
set the alignment name
04:23
to mcallister boulevard.
04:28
We'll use the layout alignment style which has different
04:31
colors for lines and curves and is ideal for designing
04:37
in the design criteria. Turn on criteria based design,
04:42
accept the default design criteria file
04:45
and set the design check set to collector.
04:50
We're going to use a fixed line to create fixed
04:53
tangents where the yellow lines are drawn in the model.
04:56
From the tool bar
04:58
under the lines, button
04:60
choose fixed line two points
05:04
using an end point snap crate lines from the
05:07
start and end of each yellow line in the drawing
05:10
zoom and pan as necessary
05:12
and press enter. When all of the lines have been created
05:21
in the model between the first two tangents,
05:24
there are a series of autocad points.
05:28
These denote positions where our curve can pass through.
05:32
We use a free curve best fit
05:35
to find the best curve that matches these points.
05:39
Pick the end of the first tangent and then the start of the second tangent
05:45
in the best fit dialogue,
05:46
select from AUTOCAD points,
05:51
select each point in turn
05:53
and then press enter
05:57
a regression data table will be displayed
05:59
which shows information about the best fit curve
06:02
and the separation between the curve and depict points.
06:07
You can see the offset on line four is rather large.
06:10
So we can exclude this point from the selection.
06:14
The curve will be recalculated,
06:16
click the save button, then dismiss the dialogue.
06:20
The curve is now placed on the alignment
06:24
for the next curve. Choose free curve filet
06:27
between two entities radius,
06:31
pick the incoming tangent. Then the outgoing tangent
06:35
and press enter to accept less than 180. For the angle
06:39
on the command line, the radius is defaulting to 1500 ft.
06:44
The minimum required by the design criteria. F
06:48
we'll ignore this and type in 1000 for the radius.
06:52
Now place the last curve
06:54
using the same options
06:57
youll need to zoom in to pick the end of the first tangent.
07:01
You will see that when we place the last curve,
07:04
the alignment is now fully labeled.
07:06
This is because all of the entities are now joined up
07:09
and the alignment is complete.
07:12
Close the layout tool bar.
07:15
Now we'll create the Sycamore Heights alignment,
07:18
open the alignment, creation tools
07:20
and rename the alignment to sycamore heights.
07:25
In the design criteria
07:26
slit use criteria based design,
07:30
make sure the design criteria file is not selected,
07:33
set the design check set to subdivision.
07:37
This time, we will lay out the alignment using intersection points
07:41
from the intersection points, pull down choose curve and spiral settings,
07:47
set the default curve radius to 140 ft.
07:51
We won't be using any spiral curves,
07:54
go back to the intersection points button
07:56
and choose tangent to tangent with curves,
08:00
turn on your center point,
08:01
object snaps and then pick the marker circles in the drawing.
08:05
In turn
08:06
where we want to place the intersection points,
08:10
curves are drawn automatically
08:12
at each intersection point
08:13
using the default radius. We've set
08:18
weve now laid out the alignments.
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