This command provides a complete set of functionality for contouring, labeling, and creating tin surface models. Given data entities that represent the surface, this command creates a final contour map with labeled, smoothed, and highlighted contours and/or a surface model that can be saved to a file (to be used in other areas of the program) or drawn on the screen as triangles or faces. Eligible data entities include points, inserts, lines, 2d polylines, 3d polylines, elevation text, 3d faces, and points from ASCII or coordinate (.CRD) files.
Triangulate & Contour has many options which are defined in the exhibits shown in the following pages. With this command, you can do any combination of drawing the triangulation network lines, drawing the contours, drawing triangulation network 3D Faces or lines, writing a triangulation file and storing a surface file.
In order to force Triangulate & Contour to correctly interpolate elevations between two points that define a grade break in the surface (such as points on a ridge, wall, or road), a breakline must exist between the points. A breakline line can be specified as a 3D polyline or line. In fact, all 3d polylines and lines with elevation are treated as breaklines.
If Triangulate & Contour reports zero points found and fails to do anything when you're using Carlson points, then those points are probably located at zero elevation. To fix this problem, make sure that Carlson Point Inserts is toggled on in the Selection tab. This will enable Triangulate & Contour to read the elevation from the elevation attribute of the point.
When Draw Triangulation Lines is turned on, the program will draw the triangulation as simple AutoCAD lines with elevation. Specify the layer for these lines in the box to the right.
When Draw Triangulation Faces is turned on, the program will draw each triangle in the triangulation network as a 3D Face. These 3D Faces can then be used in AutoCAD's modeling routines such as HIDE and SHADE or in Carlson routines such as 3D Viewer Window, 3D Surface FlyOver and Slope Zone Analysis. Specify the layer for these 3DFaces in the box to the right.
Write Triangulation File stores the triangulation surface model as an .flt or a .tin file. The .flt file format is a text file depicting the edges in the triangulation network. The .tin file is a new binary file format depicting the triangulation network. The .tin file is much faster and more efficient than the previous .flt file format. The triangulation file(s) can be used by several commands such as Volumes By Triangulation, Spot Elevations, and Profile from FLT File. Either type in the file name to create or press the Browse button to select a file name.
When Use Inclusion/Exclusion Areas is activated, the program will prompt you for inclusion and exclusion polylines. These are used to define the area of activity for triangulation and contouring. The inclusion and exclusion polylines must be closed polylines and must be drawn before using Triangulate & Contour. The command line display must be set to show at least two lines to see the prompting for the selection of the Inclusion/Exclusion perimeters.
Only the parts of the contour lines and triangles that are within the inclusion polylines will be drawn. For example, an inclusion could be the perimeter of the site. The parts of contour lines that are inside the exclusion polylines are not drawn. Exclusion polylines can be used for areas where you don't want contours such as within buildings. When Ignore Zero Elevations is activated, this setting will filter out all data points at an elevation of zero from the data set.
When Erase Previous Contour Entities is activated, this setting will erase previously drawn contour entities.
If you would
like to manually set the range over
which to contour, select the Specify Elevation Range option.
The program will automatically
contour from the lowest elevation in
the data set up to the
highest at the increment specified in Contour Interval.
The triangulation network is based on the x,y position of the points. Pick Reference Plane allows you to contour an overhang or cliff by changing the reference plane to a side view. The reference plane can be specified by first using the Viewpoint 3D command and then using the View option, or you can specify three data points on the cliff (two along the bottom and one at the top).
Highlight Breaklines highlights breaklines in the triangulation network by drawing the triangulation lines along breaklines in yellow.
Interpolate Ridges and Valleys creates
additional triangulation in a ridge or valley
situation to more accurately define the feature during surface modeling
operations. This option would commonly be used when creating a
surface model from existing contours, since it replaces the need to
manually draw 3d polylines along ridges and valleys.
Interpolate Summits and Pits creates additional triangulation in a summit or pit situation to more accurately define the feature during surface modeling operations. This option would commonly be used when creating a surface model from existing contours.
Simplify Surface is designed
to reduce the digital size of a surface, without significantly
compromising the integrity or accuracy of the surface. The most
common application is for surfaces derived from very large datasets,
such as smoothed contours. Its use is less applicable to design
surfaces or surfaces based on surveyed points, but it can still be
utilized. Simplify Surface
reduces the
size of the surface file by analyzing the difference in elevation
between each vertex of the TIN and the vertices directly surrounding
it, assigning a numerical weight or value to each vertex. If it
is determined that the calculated weight for a particular vertex is
less than the Tolerance
factor, the vertex is a candidate for removal. The number of
vertices removed is directly proportional to the Tolerance factor, so the higher the Tolerance factor, the more vertices
are removed, the lower the Tolerance
factor, the fewer vertices are removed.
If Simplify Surface is selected, the Preserve Breaklines option is activated. Preserve Breaklines further analyzes the TIN by focusing on the edges, calculating the angular difference between adjacent triangular faces. If the angular difference between edges is greater than the specified Breakline Angle, it is considered to be a breakline, and it is preserved. If it's angular difference is determined to be below the Breakline Angle, it becomes a candidate for removal. In that case, the Weight factor is applied to the corresponding vertex, adjusting it's original value. If the resulting value is still below the Tolerance, it is then removed. The number of vertices removed is inversely proportional to the Weight factor, so the greater the Weight factor, the fewer vertices that are removed, the lower the Weight factor, the more vertices that are removed.
A good rule of thumb that can be used when deciding whether or not to use these options is: if the surface contains no man-made features, use Simplify Surface only, if it contains man-made features, such as roads, use both Simplify Surface and Preserve Breaklines.
 |
| Before: Surface made from
an
existing contour map. Note the flat spots in the bottom of the valley (bottom center of the image) when Interpolate Ridges and Valleys is disabled. |
 |
| After: The same surface
with Interpolate Ridges and Valleys
enabled. Note the smooth flowline at the bottom center of the image. |
An Error Log is generated if the Triangulate
and Contour routine finds a vertical conflict between breaklines
or other surface
entities, opening the following dialog
box. Three types of conflicts are reported; Crossing
Breaklines, Vertical Edges, and Breakline T-Intersections. Crossing
Breaklines
indicates that the intersection of two entities does not have a common
elevation. Vertical Edges indicates that two entities or
vertexes of differing elevations have the same x-y location, thus
forming a vertical plane. Breakline T-Intersections indicates
that a 3d entity is abutting another entity, but the second entity
doesn't have a vertex at the point of intersection. Each type of
conflict is listed in its own category.
Clicking to the "plus" sign beside a category will display the
individual conflicts within that category. When a line item error
is selected, a highlighted arrow is temporarily placed in the drawing
to
indicate the
exact location of the specific conflict. Zoom functionality
allows the user to more closely inspect the specific problem area, and
if needed a marker can be drawn or a report generated for an
individual conflict or conflicts.
Zoom pans the drawing to move the selected conflict to the center of the screen. The zoom functions are only active when a single line item is selected.
Zoom In zooms in on the highlighted area for closer inspection. Multiple picks on the zoom button will increase the magnification.
Zoom Out zooms out away from the highlighted area.
Report All/One toggles between One and All depending whether a single line item conflict or a category is selected from the error log. An error report is generated listing the x-y position and the elevation difference of the entities in conflict.
Draw All/One toggles between One and All depending whether a single conflict or a category is selected from the list. This option draws an "X" symbol at each selected conflict. The layer and size of the symbol is controlled in the fields below.
Continue closes the
Error Log and proceeds with the
contouring operation.
Layer Name specifies the layer name for the "X"
entities drawn with Draw
One/All. This also sets the layer name for the "Draw Lines"
option.
Symbol Size specifies the size of the "X" symbol that
is drawn to delineate the
selected errors. This will determine the actual size of the
symbol in the drawing. This value is not multiplied by the
horizontal drawing scale.
In the case of crossing polylines, Draw Lines
will trace over the
polylines responsible for the conflict. The polylines will be
created in the layer specified in the layer field.
When the Draw Contours box is checked, the program will draw contour lines after triangulating. Otherwise, only the designated triangulation operations are performed. Specify the layer for contours in the edit box to the right.
Contour by Interval or Contour an Elevation determines whether to contour by interval (ie: every 10 feet) or to contour a certain elevation. The elevation option allows you to contour specific values. For example, if you want just the 100ft contour, then select elevation and enter 100. The default mode is by interval.
Use Contour Interval to specify the interval to contour. Note: If the previous option is set to Contour an Elevation, then this field is used to specify the elevation to contour.
Contour lines whose total length is less than the Min Contour Length value will not be drawn.
Reduce Vertices attempts to remove extra vertices from the contour polylines which has the advantages of a faster drawing and smaller drawing size. Default is ON When the Reduce Vertices option is
enabled, the Offset Distance value is the
maximum tolerance for shifting the original
contour line in order to reduce
vertices. The reduced contour polyline will shift no more than this
value, at any point, away from the
original contour line. A lower value will decrease the number of
vertices removed and keep the contour
line closer to the original. A higher value will remove more vertices
and allows the contour line to
shift more from the original.
When activated, the Hatch Zones option will create
hatching between
the contours
based on elevation zones. The following dialog will open allowing
the user to
specify
the hatch type and color for each elevation zone. The entire
elevation range of selected data is displayed under Current Values.
Clear clears the all of the Elevation fields in the dialog.
Load loads previous settings from a saved .pat file.
Save saves the current setting configuration to a .pat file.
Auto opens the following dialog, allowing for automatic configuration of the range of elevations in each zone, assigning of colors and hatch patterns, and the scale.
Starting Zone sets the zone with which to begin the application of the setting defined in this dialog. For Instance, if the Starting Zone was set to 10, the settings definitions applied here wouldn't affect Zones 1-9, but would start at Zone 10.
Set Values enables the Starting Value and Value Interval fields, which allow the user to specify the starting elevation for the given zone and set the zone increment.
Starting Value sets the elevation of the beginning zone to define.
Value Interval sets the elevation increment for subsequent zones.
Set Colors enables the Starting Color and Color Increment fields.
Starting Color sets the starting color number, based on the AutoCAD standard color chart.
Color Increment sets the color number to increase for subsequent zones. So if the increment was set to 5, and the starting color was 60, the next color would be 65, 70, and so on.
Set Pattern sets the hatch pattern for the defined zones.
Set Scale enables the Scale option.
Scale sets the scale for the selected hatch pattern.
Draw Index Contours creates highlighted contours at a specified interval. When enabled, the fields for Index Layer, Index Interval and Index Line Width are activated.
Use Contour Smoothing Method to select the type of contour smoothing to be performed. Bezier smoothing holds all the contour points calculated from the triangulation and only smooths between the calculated points. Polynomial smoothing applies a fifth degree polynomial for smooth transition between the triangulation faces. The smoothing factor described below affects the smoothing bulge.
Bezier Smoothing Factor The contour preview window shows
you an example of how much
smoothing
can be expected
at each setting. Sliding the bar to the left results in a lower setting
which have less looping or
less freedom to curve between contour line points. Likewise, moving the
slider to the right results
in a setting that increases the looping effect. Note that too
much smoothing applied in some situations can result in crossing
contours.
Subdivisional Surfaces / Subdivisions Generation causes each triangle in the triangulation surface model to be subdivided into an average of three smaller triangles per subdivision generation, with the new temporary vertices raised or lowered to provide smoother contours. More generations increases the smoothness of the algorithm at a cost of increased processing time. If Straight Lines are chosen as the contouring drawing method, then the contours are guaranteed never to cross. The original points of the surface model are always preserved. These modifications to the surface model are only for contouring purposes and are not written to the triangulation (.FLT) file or inserted into the drawing. If some contour movement is too small for appearance's sake, consider enabling Reduce Vertices.
When Label Contours is activated, contours will be labeled based on the settings below.
Label Layer specifies layer name for intermediate contour labels.
Index Label Layer specifies layer name for index contour labels.
Label Style specifies the text style that will be used for the contour label text.
Label Text Size Scaler specifies the size of the contour labels based on a multiplier of the horizontal scale.
Contours whose length is less than the Min Length to Label value will not be labeled.
When Break Contours at Label is checked, contour lines will be broken and trimmed at the label location for label visibility. When enabled, the Offset box to the right activates. The Offset determines the gap between the end of the trimmed contour line and the beginning or ending of the text.
When Draw Broken Segments is checked, segments of contours that are broken out for label visibility will be redrawn as independent segments. Specify the layer for these broken segments in the box to the right of this toggle.
When Label Contour Ends is checked, contour ends will be labeled.
When Draw Box Around Text is checked, a rectangle will be drawn around contour elevation labels.
When
Label Index Contours Only is checked, only the index contours will
be labeled. This
option is active only when "Draw Index Contours" has been selected in
the Contour tab of the main dialog.
Hide Drawing Under Labels activates a text wipeout feature that
will create the
appearance of trimmed segments at the contour label, even though the
contour line is still fully intact. This feature provides the
user with the
best of both worlds; you have clean looking contour labels, yet the
contour lines themselves remain contiguous. This feature will
also hide other entities that are in the immediate vicinity of the
contour label.
When Align Text with Contour is checked, contour elevation labels will be rotated to align with their respective contour lines. This option also activates the Align Facing Uphill feature explained below.
When Align Facing Uphill is checked, contour elevation labels will still be rotated to align with their respective contour lines, but the labels will be flipped in such a manner that the top of the text label will always be toward the uphill side of the contours. So as the labels are read right side up, the contours will be progressing uphill.
Use Internal Label Intervals to choose between Label Intervals or Distance Interval. Label Intervals will label each contour with a set number of labels. Distance Interval lets you specify a distance between labels.
When Specify Selection Options is checked, you can
control what type of
entities Triangulate & Contour uses. This is an
excellent method of "filtering out" unwanted entity types.
Points, 3D Polylines, 2D Polylines, Lines, Inserts are standard AutoCAD entities types.
Carlson Point Inserts refer to Carlson points which include the block SRVPNO* with the point number, elevation, and description attributes.
Spot/Bottom Elevation Inserts include text entities that start with 'X'.
From File allows you to triangulate from the points in a
coordinate (.CRD) or ASCII file. This option also provides access
to the use of Point Groups as a data source.
 |
| Label Contour Ends |
 |
 |
| Align Text With Contour ON | Align Text With Contour OFF |
 |
| Draw Box Around Text |
 |
| Original data points with one 3D polyline |
 |
| Triangulation network without contouring |
 |
| Contours
without triangulation network The contours are smoothed, reduced, drawn at an interval of 2, and highlighted at an interval of 10 with labeling on the index contours. |
Pulldown Menu Location: Contour
Keyboard Command: tri
Prerequisite: Data entities in the drawing, including
points,
inserts, lines, 2d polylines, 3d polylines, elevation text, 3d faces,
and points
from ASCII or coordinate (.CRD) files.
File Names: \lsp\tri4.lsp, \lsp\tri4.dcl, \lsp\tri4.arx