Hello everyone!
I continue developing geodetic utilities, and today I present a tool designed for building surface triangulation and contour lines.
What is it for?
I have a colleague who drafts topographic plans in plain AutoCAD without any add-ons… Let’s not discuss whether that is good or bad — there are many people who work this way.
So, my friend keeps Civil 3D installed only to generate a surface and create contours.
This utility was created specifically for people like him.
The tool allows you to:
build a triangulated surface (TIN) from a set of points, blocks, and structural lines,
generate color elevation and slope maps for better visualization,
create contour lines based on the resulting data.
Additionally, the program is capable of processing very large surface datasets even on weak computers… really weak ones :)
This makes it suitable for users who are limited in hardware resources.
The interface is available in both Russian and English.
More detailed information is provided below.
Download links are at the very bottom.
TIN Builder v1.0 — Surface Triangulation, Data Analysis & Report Generation Tool
TIN Builder v1.0 is a professional tool designed for land surveyors, topographic data specialists, civil engineers, and GIS analysts.
The program automates the creation of TIN surfaces (Triangulated Irregular Network) from DXF files, performs data quality analysis, generates elevation and slope maps, constructs contour lines, and produces a comprehensive engineering report.
The application features a fully bilingual interface (Russian / English).
Key Features
1. DXF Import and Data Analysis
The program automatically analyzes the loaded DXF file and detects all supported data types:
AutoCAD POINT entities (XYZ coordinates)
Block INSERTs, using the insertion point as an elevation
Numeric elevation values extracted from TEXT / MTEXT entities
Structural lines: LINE, LWPOLYLINE, POLYLINE (including closed polylines)
The user may choose which data sources to include when building the TIN surface.
2. TIN Surface Construction
The TIN surface is created using Delaunay Triangulation with additional engineering filters.
Triangle Filtering Options
The user can specify:
Maximum triangle edge length — removes overly stretched triangles
Minimum triangle angle — removes narrow “needle-like” triangles
Minimum triangle area — removes degenerate or tiny triangles
These filters ensure a clean, accurate, and engineer-grade surface model.
3. Structural Lines (Breaklines)
The program supports breaklines—critical structural lines representing real-world features such as berms, slope toes/crests, edges of roads, ditch lines, etc.
Structural lines:
are converted into line segments,
are checked for intersections with triangles,
force the removal and reconstruction of triangles that violate breakline geometry.
As a result, the final TIN surface correctly preserves the true terrain structure.
4. Outlier Detection
The program automatically identifies anomalous elevation points — those that deviate sharply from surrounding data due to measurement errors or manual entry mistakes.
The detection algorithm uses:
a search radius for neighboring points
a height deviation threshold (|dZ|)
Detected outlier points:
are marked with red circles in the DXF output,
are included in the engineering report,
appear highlighted on the PNG elevation and slope maps.
This helps quickly locate problematic measurements and ensures data quality.
5. PNG Map Generation
TIN Builder generates two high-quality visualization maps:
Elevation Map
color-coded from blue (low elevation) to red (high elevation),
shows the complete surface,
leaves empty areas outside the TIN boundary.
Slope Map
slope values are calculated over a regular grid,
colors represent slope steepness,
outliers are also marked on the map.
6. Contour Lines
The program can generate contour lines based on the constructed TIN:
arbitrary contour interval (e.g., 0.5 m or 1 ft),
optional major contours (every N-th line),
up to 3 levels of spline smoothing,
export to DXF separated into layers:
Layer
Content
TIN_TRIANGLES
Surface triangles (3DFACE)
TIN_OUTLIERS
Outlier points
TIN_CONTOUR_MINOR
Minor contours
TIN_CONTOUR_MAJOR
Major (thickened) contours
Contours are not generated in regions without triangles, since such areas are automatically removed from the grid.
7. Engineering Report (Report.txt)
A complete text report is generated, including:
TIN construction parameters
source data statistics
elevation range
triangle counts (before/after filtering)
outlier detection parameters
list of all detected outliers
slope statistics
contour parameters
description of created layers
references to generated files (DXF, PNG, Report)
The report is available in Russian or English, depending on the selected interface language.
8. User Interface
TIN Builder features a modern engineering-style UI:
Interface Characteristics
Instant language switching (RU/EN)
Dark theme with accent technical colors
Grouped parameter sections:
data sources
triangulation
outlier detection
contours
Log panel with detailed execution messages
DXF selection through a native Windows dialog
Built-in Help (Manual) and About sections
9. Use Cases
TIN Builder is suitable for:
surveying and geomatics companies
road and infrastructure designers
terrain model specialists
GIS engineers
UAV and LiDAR topographic processing workflows (after DXF export)
preliminary engineering calculations
field data quality control
10. Program Advantages
Fully standalone — does not require Civil 3D or other heavy CAD packages
Accepts any DXF file, including exports from field controllers
True engineering-grade TIN filtering
Correct breakline enforcement (no surface distortion)
Integrated bilingual help
Intuitive interface (no console commands required)
Automatic professional report
High-quality PNG visualizations