Integrated BIM tools, including Revit, AutoCAD, and Civil 3D
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Any referenced datasets can be downloaded from "Module downloads" in the module overview.
Transcript
00:01
PRESENTER: Welcome to the course How to Manage Large Surfaces
00:03
Efficiently.
00:04
The first objective is surface size limitations
00:07
and simplification.
00:10
Surface size limitations in Civil 3D
00:12
depend upon the surface type.
00:14
For TIN surfaces that is triangular irregular network
00:18
surfaces, 1.5 to 2 million points is the maximum.
00:23
Point clouds, points, contours, break lines,
00:27
and other three the entities are used to build TIN surfaces.
00:32
Grid surfaces have a limit of 1 million points.
00:35
They are built from digital elevation model files and ASC
00:39
and other raster files, such as GeoTIFFs.
00:44
What happens when the number of points is exceeded?
00:46
Overflow files are generated.
00:49
For TIN surfaces, when we exceed 1 and 1/2
00:51
to two million points, this creates
00:54
an overflow or a cached file.
00:56
This is a memory mapped surface file, an MMS file.
01:02
It is named with the syntax of the drawing name
01:05
and the object handle, as shown in the image on the right.
01:09
For grid surfaces, this is a 1 million point limit.
01:13
Beyond this, GRS or grid reference surface files
01:17
are created.
01:19
They have the same naming syntax but with a GRS extension.
01:24
Overflow files behave just like reference files
01:27
and must stay linked to the surface drawing.
01:30
Surface simplification is needed so
01:32
that we can avoid making MMS or GRS overflow files.
01:37
It will also give us an increase in drawing and project
01:40
performance.
01:41
And we can control the level of detail
01:44
by creating detailed and surround surfaces.
01:48
We also need to simplify to create
01:50
contour maps that better represent
01:53
the actual surface topography.
01:55
If we look at the bottom two images,
01:57
the surface on the left hand side
01:59
was created with the complete point cloud
02:02
and the surface on the right was after simplification.
02:05
You can see that after simplification, there's
02:07
a better representation of the actual surface topography.
02:12
The simplification methods for our Civil 3D surfaces
02:16
are based on the surface type.
02:18
For the TIN surface methods, we have edge contraction
02:21
and point removal.
02:23
From the images on the right, you
02:25
can see that the same amount of points have been eliminated.
02:28
But depending upon the method, the results are different.
02:32
For grid surfaces, the methods are classification filtering
02:36
and grid settings.
02:38
These were covered in a previous course.
02:43
Once you have the TIN surface, we
02:45
have two methods of simplification.
02:48
The first is point removal.
02:49
Point removal deletes the user specified percentage
02:52
of points from each region.
02:55
There's also a maximum in elevation change option.
02:59
And no points are removed resulting
03:01
in elevation changes that would result
03:04
in the surface having a greater change than that of the set
03:08
value.
03:10
The second TIN surface simplification
03:12
is edge contraction.
03:14
Edge contraction replaces the two end points of a triangle
03:18
edge with a single point and then redraws the triangles.
03:22
Remember, with both methods, points
03:24
are not removed if they are on a surface break line
03:27
or on the surface border.
03:30
Let's take a look at the difference
03:32
between edge contraction versus point removal.
03:35
The image on the left is from edge contraction.
03:39
The image on the right is the results
03:42
of removing the same number of points
03:44
but this time using point removal.
03:47
And we can see that the image on the left from edge contraction
03:51
is a better representation of a roadway
03:54
surface with side slopes.
03:56
Let's take a look at how we would
03:58
simplify a TIN surface that was created from point cloud data.
04:03
First, we attach the point cloud.
04:05
And I'm attaching an RCS file.
04:08
We'll show the details of this RCS file
04:11
that we have about 630,000 points in our point cloud.
04:21
We'll go immediately to create a surface from the point cloud.
04:26
We give the surface a name and a description and set the style.
04:35
Now we will set the distance between the points.
04:39
And this distance is the same distance
04:42
that I used for my refining grid when I exported this point
04:46
cloud from recap.
04:48
We can see that it gives us about 97% of our total points.
04:54
We select the No Filter option.
04:57
And we'll process the point clouds.
05:04
Because the point cloud is small,
05:06
it processes very quickly.
05:11
And the event viewer tells us that there are three points.
05:14
They're not included.
05:21
Next, we changed the visual style to 2D wireframe.
05:25
And I'll place the point cloud on a layer that's turned off.
05:39
Now we'll create a quick profile to show a section
05:43
across the roadway.
05:50
Next, we'll create two viewports.
05:58
And we will arrange the quick profile
06:00
on the right hand side and the contour map
06:03
on the left hand side.
06:06
I want to edit the surface style so that we
06:08
can see the triangulation.
06:11
We'll turn on the triangles in the Display tab.
06:18
And we can see that the triangulation is quite dense.
06:25
Now we select the surface.
06:27
And we go to Edit Surface and Simplify Surface.
06:34
And we will apply the edge contraction.
06:37
We want to use the entire surface.
06:40
And we can use the percentage slider
06:43
to remove 90% of the 613,000 points.
06:53
And after this processes, we can see the results of the reduced
06:57
number of triangles.
07:03
We'll repeat this again.
07:06
And we see that we have reduced the number
07:09
from 613,000 to 61,000.
07:13
So we've reduced the points by 90%.
07:16
And now we will reduce by another 90%
07:20
to end up with about 6,000 points.
07:24
And this gives us a clearer representation
07:28
of a roadway with a center median and a sidewalk.
07:32
One word of caution when using the surface simplification
07:35
tools, you have to understand how
07:38
Apply, Finish, and Cancel work.
07:41
Apply and Finish will run the surface simplification.
07:45
Cancel will exit without simplifying.
07:48
In this example, we began with over 613,000 original points.
07:54
We clicked on Finish to remove 90% of those points.
07:59
This resulted in a surface with only 61,000 points.
08:04
If I hit Cancel, no additional points would be removed.
08:08
The next time I use simplification,
08:11
if I hit apply or finish, then an additional 90% of points
08:16
will be removed and will result in just over 6,000 points,
08:21
which was the final result of the surface.
08:26
Remember, to improve the true representation of the existing
08:29
conditions, you may need to do some manual editing
08:33
and even add more data.
08:35
We can do this by adding brake lines
08:38
and using stepped offsets.
08:40
We can improve the contours.
08:42
And we can add extra data points or entities.
08:46
As you can see from the image on the bottom,
08:48
by adding brake lines to define center islands, medians,
08:52
and the edges of travel ways, we have a very good representation
08:57
of the existing conditions surface.
08:60
The next objective in this course
09:02
is controlling LOD with detail and surrounds surfaces.
Video transcript
00:01
PRESENTER: Welcome to the course How to Manage Large Surfaces
00:03
Efficiently.
00:04
The first objective is surface size limitations
00:07
and simplification.
00:10
Surface size limitations in Civil 3D
00:12
depend upon the surface type.
00:14
For TIN surfaces that is triangular irregular network
00:18
surfaces, 1.5 to 2 million points is the maximum.
00:23
Point clouds, points, contours, break lines,
00:27
and other three the entities are used to build TIN surfaces.
00:32
Grid surfaces have a limit of 1 million points.
00:35
They are built from digital elevation model files and ASC
00:39
and other raster files, such as GeoTIFFs.
00:44
What happens when the number of points is exceeded?
00:46
Overflow files are generated.
00:49
For TIN surfaces, when we exceed 1 and 1/2
00:51
to two million points, this creates
00:54
an overflow or a cached file.
00:56
This is a memory mapped surface file, an MMS file.
01:02
It is named with the syntax of the drawing name
01:05
and the object handle, as shown in the image on the right.
01:09
For grid surfaces, this is a 1 million point limit.
01:13
Beyond this, GRS or grid reference surface files
01:17
are created.
01:19
They have the same naming syntax but with a GRS extension.
01:24
Overflow files behave just like reference files
01:27
and must stay linked to the surface drawing.
01:30
Surface simplification is needed so
01:32
that we can avoid making MMS or GRS overflow files.
01:37
It will also give us an increase in drawing and project
01:40
performance.
01:41
And we can control the level of detail
01:44
by creating detailed and surround surfaces.
01:48
We also need to simplify to create
01:50
contour maps that better represent
01:53
the actual surface topography.
01:55
If we look at the bottom two images,
01:57
the surface on the left hand side
01:59
was created with the complete point cloud
02:02
and the surface on the right was after simplification.
02:05
You can see that after simplification, there's
02:07
a better representation of the actual surface topography.
02:12
The simplification methods for our Civil 3D surfaces
02:16
are based on the surface type.
02:18
For the TIN surface methods, we have edge contraction
02:21
and point removal.
02:23
From the images on the right, you
02:25
can see that the same amount of points have been eliminated.
02:28
But depending upon the method, the results are different.
02:32
For grid surfaces, the methods are classification filtering
02:36
and grid settings.
02:38
These were covered in a previous course.
02:43
Once you have the TIN surface, we
02:45
have two methods of simplification.
02:48
The first is point removal.
02:49
Point removal deletes the user specified percentage
02:52
of points from each region.
02:55
There's also a maximum in elevation change option.
02:59
And no points are removed resulting
03:01
in elevation changes that would result
03:04
in the surface having a greater change than that of the set
03:08
value.
03:10
The second TIN surface simplification
03:12
is edge contraction.
03:14
Edge contraction replaces the two end points of a triangle
03:18
edge with a single point and then redraws the triangles.
03:22
Remember, with both methods, points
03:24
are not removed if they are on a surface break line
03:27
or on the surface border.
03:30
Let's take a look at the difference
03:32
between edge contraction versus point removal.
03:35
The image on the left is from edge contraction.
03:39
The image on the right is the results
03:42
of removing the same number of points
03:44
but this time using point removal.
03:47
And we can see that the image on the left from edge contraction
03:51
is a better representation of a roadway
03:54
surface with side slopes.
03:56
Let's take a look at how we would
03:58
simplify a TIN surface that was created from point cloud data.
04:03
First, we attach the point cloud.
04:05
And I'm attaching an RCS file.
04:08
We'll show the details of this RCS file
04:11
that we have about 630,000 points in our point cloud.
04:21
We'll go immediately to create a surface from the point cloud.
04:26
We give the surface a name and a description and set the style.
04:35
Now we will set the distance between the points.
04:39
And this distance is the same distance
04:42
that I used for my refining grid when I exported this point
04:46
cloud from recap.
04:48
We can see that it gives us about 97% of our total points.
04:54
We select the No Filter option.
04:57
And we'll process the point clouds.
05:04
Because the point cloud is small,
05:06
it processes very quickly.
05:11
And the event viewer tells us that there are three points.
05:14
They're not included.
05:21
Next, we changed the visual style to 2D wireframe.
05:25
And I'll place the point cloud on a layer that's turned off.
05:39
Now we'll create a quick profile to show a section
05:43
across the roadway.
05:50
Next, we'll create two viewports.
05:58
And we will arrange the quick profile
06:00
on the right hand side and the contour map
06:03
on the left hand side.
06:06
I want to edit the surface style so that we
06:08
can see the triangulation.
06:11
We'll turn on the triangles in the Display tab.
06:18
And we can see that the triangulation is quite dense.
06:25
Now we select the surface.
06:27
And we go to Edit Surface and Simplify Surface.
06:34
And we will apply the edge contraction.
06:37
We want to use the entire surface.
06:40
And we can use the percentage slider
06:43
to remove 90% of the 613,000 points.
06:53
And after this processes, we can see the results of the reduced
06:57
number of triangles.
07:03
We'll repeat this again.
07:06
And we see that we have reduced the number
07:09
from 613,000 to 61,000.
07:13
So we've reduced the points by 90%.
07:16
And now we will reduce by another 90%
07:20
to end up with about 6,000 points.
07:24
And this gives us a clearer representation
07:28
of a roadway with a center median and a sidewalk.
07:32
One word of caution when using the surface simplification
07:35
tools, you have to understand how
07:38
Apply, Finish, and Cancel work.
07:41
Apply and Finish will run the surface simplification.
07:45
Cancel will exit without simplifying.
07:48
In this example, we began with over 613,000 original points.
07:54
We clicked on Finish to remove 90% of those points.
07:59
This resulted in a surface with only 61,000 points.
08:04
If I hit Cancel, no additional points would be removed.
08:08
The next time I use simplification,
08:11
if I hit apply or finish, then an additional 90% of points
08:16
will be removed and will result in just over 6,000 points,
08:21
which was the final result of the surface.
08:26
Remember, to improve the true representation of the existing
08:29
conditions, you may need to do some manual editing
08:33
and even add more data.
08:35
We can do this by adding brake lines
08:38
and using stepped offsets.
08:40
We can improve the contours.
08:42
And we can add extra data points or entities.
08:46
As you can see from the image on the bottom,
08:48
by adding brake lines to define center islands, medians,
08:52
and the edges of travel ways, we have a very good representation
08:57
of the existing conditions surface.
08:60
The next objective in this course
09:02
is controlling LOD with detail and surrounds surfaces.
To easily control the visibility of the point cloud, it will be placed on its own unique layer.
A quick profile is used to quickly look at a section across the roadway. A named viewport will be used to split the view between the plan view and the quick profile view so that the profile view can be manipulated using grips on the defining line.
Using surface simplification methods, the surface contour map and section view will improve to better represent a roadway with side slopes condition.
Performing an additional Surface Simplification will further reduce the number of points and the TIN density of the surface.
Repeat the procedure in Task 8 – note that the number of points is now about 61375. Use the same 90% reduction value and click on Finish.
This simplification gives a TIN surface that displays contours and a Quick Profile section that represents a roadway separated by a median with side slopes and sidewalks on the northern side.
The original surface had over 600 thousand points and after two simplification steps using Edge Contraction at 90% the resulting surface has just over 6 thousand points. This results in a very efficient surface with the number of points much lower than the maximum number of 1.5 million points.
You do not need to save this Civil 3D drawing.
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