CesiumGS/cesium-unreal-samples

Wrong `TimeZone` on `CesiumSunSky` in various levels

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#69 opened on Jan 22, 2026

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good first issue

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Description

Levels like 01_CesiumWorld and 02_CesiumMelbourne use a time zone that is not actually accurate to the region. Then, the solar time is set very early or late to compensate.

This isn't a problem when simply opening + viewing the level, but if you ever try to reposition the georeference, it updates the timezone for that longitude. This can result in total darkness if the solar time is late at night.

Contributor guide

Research direction
Inspect the levels 01 CesiumWorld and 02 CesiumMelbourne in CesiumSunSky to understand how timezone is set. Check the CesiumSunSky source for timezone handling and see how it interacts with georeference updates.
Tech stack
cpp
Domain
backendapi
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Unreal EngineCesium for Unreal
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60