Problem

Using Trail Renderer to draw vertical trails or walls can produce incorrect results when the object has a non-zero Z transform or moves in 3D space.
The issue is discussed here:
https://discussions.unity.com/t/vertical-line-using-line-renderer-with-transform-z/762604

Solution

VerticalTrailRenderer-script that generates a mesh, to draw vertical trail.
It records object movement and builds a vertical quad strip using a Mesh rendered by a MeshRenderer.

• vertical trail generated from movement points
• configurable lifetime and fade
• no GC
• full rendering options (render layer ,shadows, probes, bounds etc)
• optional double sided geometry

Installation

1. install as package by Git URL
2. Place the script VerticalTrailRenderer.cs anywhere inside Project/Assets/ in a Unity project

Usage

• Add the script to a GameObject.
• Assign a material to _trailMaterial.
• Move the object — the script generates a vertical trail mesh automatically.