I’m reporting a critical flaw in iClone’s rendering system.

The viewport preview does not match the final render output.
Lighting that looks correct in real-time becomes drastically darker, harsher, or completely different when using “Final Render.” The “Preview Render” option is the only one that matches the viewport, which defeats the purpose of lighting work.

This is NOT user error.
This is the software using two different shading engines and presenting them as if they will match. The result is hours of wasted lighting work because the viewport lies.

For expensive professional software, this is unacceptable.

What I need from Reallusion:

A confirmation that this is a known issue

A fix or patch to unify the viewport and final render engine

Documentation that clearly explains the differences between the render modes

A way to force the viewport shading mode for ALL renders

This problem cost hours of work and nearly caused me to abandon the project.
Other users are experiencing the same issue — please escalate this internally.