build lighting in raytrace mode?

[anonymous_user_491d25cb]

Should I “build lighting” when using ray-tracing?
Because I have a feeling that my reflection are not showing up on my metallic materials even with a reflection probe in the scene?

[MostHost_LA]

Ray tracing is (usually at least?) real-time, not baked.

That said if your reflection captures are not using Raytracing and/or your materials are falling back on reflection captures, then building reflection captures May help…

There is also a general fallback for when no reflecrion capture provides a texture I believe. But generally if you are using properly set raytracing reflections those aren’t required. They act as a fallback for when raytracing is disabled if you build for it.

[anonymous_user_491d25cb]

@MostHost_LA

Ray tracing is (usually at least?) real-time, not baked.

That said if your reflection captures are not using Raytracing and/or your materials are falling back on reflection captures, then building reflection captures May help…

There is also a general fallback for when no reflecrion capture provides a texture I believe. But generally if you are using properly set raytracing reflections those aren’t required. They act as a fallback for when raytracing is disabled if you build for it.

and I guess raytrace reflection is only enabled in the camera?

[MostHost_LA]

From docs:

Ray Traced Reflections

Ray Traced Reflections (RTR) simulates accurate environment representation supporting multiple reflection bounces.

This example shows a single bounce of ray traced reflections compared to multiple bounces of ray traced reflection. Using multiple bounces creates real-time inter-reflection between reflective surfaces in the scene.

https://forums.unrealengine.com/core/…/…/…/…/Images/Engine/Rendering/RayTracing/RTR_SingleBounce.jpg
Ray Traced Reflection Single Bounce

https://forums.unrealengine.com/core/…/…/…/…/Images/Engine/Rendering/RayTracing/RTR_MultipleBounces.jpg
Ray Traced Reflections Multiple Bounces

In contrast, Screen Space Reflections (SSR), Planar Reflections , or even Reflection Capture Actors cannot capture the entire scene dynamically nor does it have some of the limitations present in these other reflection methods.

In this comparison, SSR is only capable of a single reflection bounce and is limited to what is visible on the screen for representation. On the other hand, RTR is capable of multiple bounces and is not limited to what is visible, meaning that we can visibly see the sides of the book, reflected floor behind the camera, and additional lightings being reflected on surfaces coming through the window.

And
https://docs.unrealengine.com/en-US/…ngs/index.html

The settings are sprinkled around. Search for reflection on that page and go enable the relative result.

[Suthriel]

The important part is this one, and you can control those settings via a post process volume:

[TABLE]

Ray Tracing Reflections

Max Roughness
Sets the maximum roughness value that Ray Traced Reflections will be visible before falling back to raster methods that are less expensive. Reflection contribution is smoothly faded when close to the roughness threshold and this parameter behaves similarly to SSR’s Max Roughness setting. Lower values fall back to other methods more quickly.

For every material and pixel, that have a roughness lower than what is set in “Max Roughness” will use raytraced reflections, materials/pixels with roughness above that will use reflection captures. It´s for performance reasons, and noise reduction, that usually comes with very rough materials and low samples for raytraced reflections.