I found this thread after searching for the reason for my pain, when unexpectedly I discovered time overhead, when I hit F12 just before actual rendering, lots of it in a somewhat heavy scene.
- This time delay does not exist in viewport renders
- This delay is independent of the render engine delaying Cycles and Eevee and Workbench final renders.
Looking around for the cause I found people calling it Build Time, others calling it BVH and I recall there is a thing called Syncing Time, all seeming to be calculations before the start of actual rendering.
Are these all the same? am I in the right thread?
I also do ArchViz and render still images 99% of the time. I would batch them up and run them from the command line, in that case the calculation time, called Syncing, would only happen once and all frames would then be rendered without additional such calculation. What happens with command line rendering, cannot be done inside Blender interactive environment?
The scene I’m working on now has about 800K faces and takes about 3 minutes to prepare (for any of the 3 built in engines Cycles, Eevee, Workbench), larger model than usual, because I am trying “Tissue” addon for the first time, which generates lots of geometry parametrically. It is still easily manageable refreshing in the viewport instantaneously with Workbench (Solid shade), almost instantaneous with Eevee, and a few seconds in Cycles with great Optix denoising.
EDIT: My bad, I did testing with WorkBench, Eeevee and Cycles. Testing was rendering from the cmd line in the background, 10 frames. The Workbench delays in final render were due to the setting “5 passes anti-aliasing” with 1 pass it was much faster. I was also wrong about syncing, it is done for every frame (each of my frames is bound to a different camera). Surprisingly the faster of the 3 engines was Cycles (Optix with RTX 2070, Blender 2.91.0, under Windows 10 X64)
- Workbench with 1 single pass antialiasing
- Eevee with 128 samples (maybe more than needed…)
- Cycles with 150 samples and Optix denoising
I piped the message outputs tracking the progress to a file for each of the 3 engines:
1cy.txt (11.6 KB) 1ev.txt (59.0 KB) 1wb.txt (5.8 KB)
@bliblubli Matthieu I did not understand you, does E-Cycles deal with this delay?