How to Edit a TIN Surface in BricsCAD

Quick answer: TINEDIT adds or removes points, breaklines, and boundaries on an existing TIN surface, the same three feature types used when originally creating one.

Adding Points to a TIN Surface

1. Open a TIN surface that already has points.
2. Select the surface and launch TINEDIT.
3. Click an area to add a point. Its value is calculated as the interpolated elevation for that point within the surrounding triangle. With ESNAP on, you can check the elevation at the cursor’s current position.
4. To set a specific elevation instead, type a value at the Command line and press Enter.
5. Keep adding points, or press Enter to exit. New surface points can also come from entities like polyline vertices.

Adding Breaklines to a TIN Surface

1. Open a TIN surface.
2. Select it and launch TINEDIT.
3. Choose Add Breaklines, or type AB at the Command line.
4. Select the breaklines you want to add; the surface modifies to match them.

If a breakline is moved afterward, the surface updates automatically, the same live connection covered on the TIN surface creation page.

Adding Boundaries to a TIN Surface

1. Open the TIN surface where you want the boundary.
2. Create a closed boundary at the location where you want to clip the surface. Make sure entity snaps (the ESNAP field in the Status Bar) are active; note that despite how this is sometimes labelled, ESNAP itself toggles entity snap modes generally, not entity snap tracking specifically, which is a separate feature (STRACK).
3. Select the TIN surface and launch TINEDIT.
4. Choose Add Boundaries.
5. Click the closed boundary to use, then press Enter.

By default, the outer option is selected, creating an outer surface boundary. From there:

• Select the bounding entity (a polyline, for example) and move its grip to resize the surface boundary dynamically.
• Choose the hide option to exclude part of the surface from the TIN’s total area calculation.
• Choose the show option to reveal a previously hidden part of the surface again.

Frequently Asked Questions

What elevation does a newly added TIN point get by default? An interpolated value based on the surrounding triangle, unless you type a specific elevation at the Command line instead.

Does moving a breakline update the TIN surface automatically? Yes, once a breakline is added to a surface, moving it later updates the surface to match.

What’s the difference between the hide and show boundary options? Hide excludes part of the surface from the TIN’s total area calculation. Show reveals a part that was previously hidden this way.

Can I resize a TIN surface’s boundary after creating it? Yes, select the bounding entity and move its grip; the surface updates dynamically to match the new boundary shape.