How to Analyse TIN Surfaces in BricsCAD

Quick answer: TINVOLUME calculates the exact difference between a base and comparison surface (or a fixed elevation), useful for earthworks calculations. TINWATERDROP visualizes drainage paths across a TIN surface in real time.

About TIN Volume

A TIN volume surface gives the exact difference between two surfaces: the Z-value at any point equals the comparison surface’s Z at that point minus the base surface’s Z there. It’s drawn as a custom entity carrying its own fill and cut volume properties, and is useful for:

• Calculating fill and cut volumes within a bounding area.
• Drawing zero contours that divide fill areas from cut areas.
• Visualizing mass distribution across a site.

Setting TIN Volume Associativity

Choose whether a TIN volume surface stays associative, automatically updating whenever the base or comparison surface changes.

1. Run SETTINGS.
2. Go to Civil > Civil General > Associativity.
3. Tick or untick “TIN Volume Surfaces are associative.”

This corresponds to the TIN volume surface bit of the CVASSOCIATIVITY variable, the same associativity setting covered on the TIN surface creation page, just accessed here as its own dedicated checkbox rather than the full bitcode.

Creating a TIN Volume from a Comparison Surface

1. Launch TINVOLUME.
2. Choose a base surface.
3. Choose a comparison surface.
4. Select a bounding area, or press Enter to use the surface’s outer boundary by default.

The TIN Statistics category then shows the cut and fill volume inside the bounding area. The Data category shows the volume surface’s name, description, and read-only references to its base surface, comparison surface, and bounding polygon.

Creating a TIN Volume Using Elevation

1. Launch TINVOLUME.
2. Choose a base surface.
3. Choose the Elevation option.
4. Choose the elevation height.
5. Select a bounding area, or press Enter to use the surface’s outer boundary by default.

Creating a TIN Volume Report

1. Launch TINVOLUMEREPORT.
2. Choose a TIN volume surface.
3. Pick a point in the drawing to insert the report as a table, or export it to a CSV file instead.

Creating a Water Drop Path

1. Launch TINWATERDROP.
2. Select the TIN surface.
3. Move the cursor over it; a real-time preview of the drop path displays. Changing the current layer to a distinct colour (red, for example) makes the path easier to see.
4. Left-click to create the path as a 3D polyline.

Frequently Asked Questions

What does the Z-value of a TIN volume surface actually represent? The exact difference between the comparison surface’s elevation and the base surface’s elevation at that point.

Does a TIN volume surface update automatically if I change the base or comparison surface? Only if associativity is turned on, via Settings > Civil > Civil General > Associativity, the same setting covered by CVASSOCIATIVITY.

Can I export a TIN volume report instead of inserting it as a table? Yes, TINVOLUMEREPORT lets you export directly to a CSV file as an alternative to inserting a table in the drawing.

How do I make a water drop path easier to see once created? Change the current layer to a distinct colour, like red, before creating it.