Hi,
I’ve noticed that in 2.83 cycles takes longer time to initialize, update BVH and such stuff then in 2.82. On the file I investigated it went from ~5s in 2.82 to ~27s in 2.83. Does anyone have any idea about where I can start looking for causes and solutions?
Is there any specific test files I could run or debug messages to look for somewhere?
Hello again guys,
Wanted to bump this topic before bugging the devs with bugreports. I made my experiment again with The Junk Shop scene and got the following results:
2.82a
Time for cycles initialization: 7.9s
Time until the first sample of the picture is seen: 14s
2.83
Time for cycles initialization: 18s
Time until the first sample of the picture is seen: 22.6s
Can anyone reproduce this? Please, if you still have 2.82 installed try this and see if it’s just me getting crazy or if there really is this big difference I understand there can be changes that makes some percent differences between versions, but +60% in total pre-render time seems excessive to me.
I will try to test some of my scenes, although they are not that complex or big anyway.
Is there a way you use to measure time or do you just copy the time the moment the initialization is done?
Thanks!
The times above are for viewport rendering so I just time it with a stop watch. Perhaps a bit inexact but it seems accurate down to half a second at least.
I haven’t yet checked the initialization times for final renders since they don’t impact my work that much. But if it would be interesting for someone I’ll check that too of course!
Sorry to disappoint but I can’t currently find a heavy enough scene to test it . All the scenes I have tested just initialize quickly enough that I can’t record it, in both versions.
I also can’t download any of the showcase scenes due to the slow internet currently.
I will make sure to post my results if I ever found a worthy scene.
@watercycles Strange… Thanks for the Optix vs Cuda idea! I redid my tests with all computing devices, see below, but still the same results on my side.
@okm1123 No problems. Thanks for checking it out anyways!
Some more results for those interested:
The Junk Shop pre render times
2.81a init
2.81a tot
2.82a init
2.82a tot
2.83 init
2.83 tot
2.90.0 init
2.90.0 tot (9f7d84b656fb)
CUDA CPU
7.8s
25.3s
7.8s
13.9s
18.0s
23.1s
18.1s
23.3s
CUDA GPU (CPU+RTX)
8.0s
25.3s
8.2s
13.9s
18.6s
23.0s
18.1s
22.8s
CUDA GPU (Only RTX)
8.0s
13.9s
7.8s
13.7s
18.1s
23.0s
18.2s
22.9s
Optix
8.0s
10.7s
7.8s
10.5s
18.3s
19.6s
18.5s
19.5s
To me these times seems consistent enough to show that there are differences. But I’m still not sure that the fault isn’t located between the chair and the keyboard. Is there any other settings I should check for?
We seem to agree on the init of 2.83. It seems strange that 2.82a is so much faster. I guess the init never bugged me because when I switch to render preview I’ll just leave it there for a while.
The only other thing I would think of is to disable all your plugins except for Cycles?
Thanks! Good to know I’m not alone at least.
I disabled all plug-ins except cycles and did the same tests in 2.83 again. Unfortunately I got exactly the same pre-render times again.
If the init times would only happen when starting the preview render I wouldn’t mind it much. My main problem is that some operations, like rotating background hdri and such, seem to provoke the init times again. This makes fine adjustments extremely frustrating
For me the init times do only happen when starting the preview render. When I rotate hdri via the mapping node it takes a fraction of a second to update. I also tried moving stuff in the Junk Shop scene and again it updates almost instantly. Changing materials same.
Try installing Octane for Blender. What are the init times there and does it reinit after making some changes?
Yes it seems like it’s just certain older documents that show excessive pauses while working on the materials. I thought it was connected to the init times, but perhaps that a erroneous conclution. I’ve got those documents from a former colleague of mine and I think they are pre 2.8x even. Maybe I should just import everything in a fresh 2.83 file and see if that solves it.
Installing Octane is a neat idea. Never tried another engine since I’m happy with cycles but if I don’t solve the problems through other means that’s a good course of action. Thanks for the idea!
I understand there can be changes that makes some percent differences between versions, but +60% in total pre-render time seems excessive to me.
. All the scenes I have tested just initialize quickly enough that I can’t record it, in both versions.
