The probe mode can be none, fps or metrics. To enable the probe, set the probe mode in the engine parameters. Then enable the probe in scenes where it is needed. An overlay must be active for the probe to work. The probe is automatically disabled when changing or closing overlays. The FPS will update once a second. To toggle metrics, press Ctrl+F12. Metrics are only updated when Ctrl+F12 is pressed, as extracting metrics data from the scene impacts performance.
APP - App unpaged size / App paged size / App paged items
GPU - GPU unpaged size / GPU paged size / GPU paged items
RAY - Primary rays required by output resolution
TRI - Total number of triangles
MAT - Total number of materials
PRM - Primary (always 1)
SDW - Shadow
RFR - Refraction
RFL - Reflection
BGD - Background
RPP - Total
LTH - In range and calculated. (hit)
LTM - Not in range and not calculated. (miss)
RPF - Rays per frame
RPS - Rays per second