Basic level template with NVIDIA FleX framerate issues

[Wizman87]

I have a very basic level template that I use for testing and it is running into some very heavy NVIDIA FleX framerate issues. The framerate will tank below 20-40 FPS whenever a varied amount of clustered zeds die anywhere in the level. Naturally, if the NVIDIA FleX "Gibs AND Fluids" video option is turned off, the issue goes away completely. With NVIDIA FleX disabled, the framerate remains at a constant 60 FPS. This issue does not occur in any other levels.

I have never once had this issue occur in the past with any of my previously created levels. That is why I am trying to understand the issue now so that I do not reproduce it again in the future. All of the other levels that I created, in addition to those of other user-generated and officially released levels, work and play perfectly with NVIDIA FleX enabled. The issue only lies with this one level.

Can anyone help explain the issue and why it might be occurring? I would like to understand how or why it happens, as well as see if there are any possible fixes for it. My only assumption at this point in time is that the issue is being caused by the rendering of physics, splattermaps, lighting, and/or shadows in the level. If anyone needs a reference to the level, let me know, and I will try to upload it.

Thank you for the help!

 

[Seanchaoz]

I've been having my share of flex headaches with level design as well. Massive FPS drops from 100+ into the sudden 20-30 range, and I believe I've tracked down at least some of the culprits.

1. A huge FPS hog with Flex seems to be Light Density and Per Object Shadows. Now these two are candidates for basic performance optimization that you should always be mindful about no matter what level you are making, but when adding Flex into the mix it can really cause massive meltdowns. My uneducated guess is because every piece of "gib" and blood/fluid that spawns has to receive dynamic light info and cast dynamic shadows individually from every light that hits it. So if you have zeds gibbing inside an area with many overlapping lights that allow per object shadows, you can see how things can get out of hand very quickly.

Things you can do (and should do regardless) is try to keep lights from overlapping wherever you can, and make sure they only allow per object shadows if it is REALLY necessary. By far most lights (point lights especially) don't need to cast per object, and if you feel they do, then make sure the ones that do especially do not overlap.

2. Overlapping emitters seem to also don't play too nicely with Flex, try to avoid where you can. Especially if they are inside lights.

3. Complex/many collision models might also have some negative impact on flex and fluids. Combining meshes and creating simple collisions for them might improve flex issues a bit. Alternatively try wrapping troublesome collision areas in fluid volumes. You can copy/paste the ones from many of the official maps and resize them to your needs, they are the checkered blue/white boxes you often see placed on stairways and handrails.

4. Make sure you've done a full light build before testing. Unbuilt light can cause FPS issues in-game.

 

[Wizman87]

This was very informative! I will definitely remember this information and apply it in my future levels! Thank you for taking the time to write a great post!

As for my current level, I will mess around with the lighting and shadow settings a bit. I will update everyone if I stumble upon anything. Cheers, Seanchaoz.