This style generates 'violin' lines in the form of m-buffered strokes, where the width is based on the value sampled from a raster layer (normally 1-band elevation data).

The most important settings can be changed in the beginning of the script.

The style is tested with temporary scratch layers with a single polygon feature. Multiple features will trigger the style to generate multiple times (slower).

Try to be consistent regarding layer coordinate systems...

CRS: vector_layer = elevation_layer = project