TIN Surfaces

NullCad can build Triangulated Irregular Network (TIN) surfaces from selected points, using a Constrained Delaunay Triangulation.

Creating a surface

1. Select the points you want to triangulate.
2. Activate the TIN Surface tool (Surface & Drafting category).
3. Optionally add hard or soft breaklines to constrain the triangulation along known features (e.g. a ridge line or a drainage line).

Non-destructive

Building a TIN surface never modifies the source points — the surface is a separate geometry object (TinSurface) that references the input data, so you can regenerate or delete the surface without losing the underlying point data.

Breaklines

• Hard breaklines force triangle edges to follow the breakline exactly — used for discontinuities like retaining walls or building edges.
• Soft breaklines influence triangulation without forcing a hard edge — used for smoother features like ridge or valley lines where a small amount of triangle flexibility is acceptable.