kirra-docs

Surface Gradients

Kirra supports multiple gradient visualisation modes for surfaces, applied in both the 2D canvas and 3D views.

Screenshot coming soon – comparison of gradient modes on the same surface

Available Gradients

Gradient	Description	Best For
Default	Simple elevation-based blue-to-red	Quick visualisation
Hillshade	Lighting simulation for topographic relief	Terrain analysis, slope identification
Viridis	Perceptually uniform purple-teal-green-yellow	Scientific data, accessibility
Turbo	Rainbow-like high dynamic range	Maximum visual contrast
Parula	MATLAB-style blue-green-yellow	Engineering applications
Cividis	Colourblind-friendly blue-yellow	Accessibility
Terrain	Green-brown natural palette	Natural terrain appearance
Texture	Original OBJ texture map	Photo-realistic (requires textured OBJ import)

How to Change the Gradient

Right-click the surface in the TreeView or 3D view
Select Surface Properties
Choose a gradient from the dropdown
Click Apply
The surface updates in both 2D and 3D views

Elevation Limits

By default, the gradient maps across the surface’s full elevation range (minimum Z to maximum Z). You can narrow this range to improve contrast in a specific elevation band:

Min Limit – Elevations below this value are clamped to the gradient’s lowest colour
Max Limit – Elevations above this value are clamped to the gradient’s highest colour

Set these in the Surface Properties dialog.

Hillshade Settings

The hillshade gradient simulates directional lighting on the surface:

Hillshade Colour – Base colour for the shading (default: grey)
Azimuth – Light direction, 0-360 degrees (default: 315 deg = northwest)
Altitude – Light angle above horizon, 0-90 degrees (default: 45 deg)

Hillshade is useful for visualising terrain features such as ridges, valleys, and slopes, and for checking DTM accuracy.

Transparency

The transparency slider controls surface opacity:

0 = fully transparent (invisible)
1 = fully opaque (solid)

Transparency can be adjusted at any time, including after applying blast analytics overlays.