How the off-screen render buffer works
Marvel Rivals renders through Unreal Engine's D3D12 swap chain. OBS's Game Capture, Discord screen-share, NVIDIA ShadowPlay, and Windows Game Bar all hook the same swap chain — they intercept the frame after the game has finished drawing it and grab the back buffer. That is why those tools can capture a game without the user clicking anything: they are reading the pixels at the same point the monitor reads them.
Nimbus draws its overlay into a separate D3D9 surface that sits in its own popup window outside the Marvel Rivals swap chain. The popup is rendered into a region the monitor composites at present time, which is what your eyes see, but it is never inside the buffer those capture tools intercept. The technical name for this in the public reverse-engineering literature is an off-screen or sidecar render — same idea as a transparent WS_POPUP layered window with click-through input. The result is a clean Marvel Rivals capture for your stream and a complete overlay for you.
Where it does NOT help — Display Capture
OBS Display Capture, NVIDIA full-desktop capture, and a hardware capture card pulling the HDMI output all see the literal monitor signal. Anything on the monitor — overlay included — is captured. If you stream with Display Capture because of black-screen issues on Game Capture, you have two choices: switch to Game / Window Capture (the underlying cause is usually a fullscreen-exclusive setting in Marvel Rivals) or disable the overlay before going live. The launcher Settings tab has a single toggle that disables the entire overlay render — no menu, no aimbot, no ESP — when you need to stream a clean session.
Stream-safe is not the same as ban-safe
A common conflation: “stream-safe” and “undetected” are different problems. Stream-safe is about whether OBS sees the overlay; undetected is about whether Easy Anti-Cheat sees it. Off-screen rendering solves the first; the second requires a completely separate set of choices, which the smart-aim alternative page and the are overlays safe blog post walk through. Both pages, plus our ban-recovery write-up, are required reading if your goal is “keep streaming, stay un-banned” rather than just “keep the overlay out of the clip.”
Testing it on your own setup before you go live
The five-minute test: launch Nimbus, launch Marvel Rivals, open OBS or Discord screen-share with Game Capture set to Marvel Rivals, and check the preview window. The overlay should not appear. Then switch to Display Capture and confirm it does appear — that is the control case that proves the test is meaningful. Repeat with ShadowPlay (Alt+F10 records a fifteen-second clip) and play the clip back; the overlay should be gone.
If anything in that test is unexpected, ping the #creators channel on the Nimbus Discord — capture-tool versions move fast and the channel is where the working configurations live.
Other reading creators ask about
For setup time before going live, see the 90-second install walkthrough. For the EAC compatibility surface, see Marvel Rivals EAC explained. For the comparison vs other Marvel Rivals overlays on the stream-safety dimension specifically, see the comparison page.