Lets talk a little abut shadow casting lights.

[jojje5]

So i have been reading allot of modding guides that tells that i should only use one shadow casting light per room (or is it per cell? different guides tell different things)

otherwise i could get into severe trouble (?)

 

However i don´t seem to have any trouble throwing in 30+ shadow casters in a cell using my R9 380 AMD card, a card that i think is considered rather low end today,

granted that i don´t pack the shadow casters too close together.

 

so who exactly are these guides for? is this recommendations when modding for consoles or something?

what exactly are the trouble i can run into and when does it happen?

 

I would be very happy for any experience shared regarding modding with shadow casters.

 

cheers.

[MissingMeshTV]

IMHO, that rule of thumb is still valid. Take it from someone who learned the hard way, just because your machine can handle a large number of shadowed lights doesn’t mean everyone’s will. After an extended play session where everything runs fine, it just takes hitting one cell with too many shadows to turn the game into a slideshow. Not everyone has this happen, but you can’t assume that because it doesn’t happen to you it won’t happen to other people. The game engine has seen some good improvements, but it can (and will) choke on cells with too many shadowed light sources. Which is a shame, because shadows are one of the things I feel it excels at.

 

My first big player home mod had many (maybe 10-15) shadowed light sources. I tested it on three machines, including a potato laptop with a lousy GTX860M. I had no issues in playing for an hour or two, running in and out of the cell. First day the mod gets uploaded, people complain of frame rate drops and slideshows entering the cell. It became a common and frequent complaint, even from users with beefy rig specs.

 

It was nothing I was ever able to replicate on my end after many hours of trying, until one day after a good four straight hours of game play I went to load into the cell, and BAM…slideshow. I eventually removed all but a few shadowed lights (left a few spotlight shadowed) and there hasn’t been a single performance issue reported in many months. The problem was apparently solved.

 

So, I still go by the one shadowed light per room guideline and will vary it by the size of cell and level of clutter, scripting, etc. that is going on just to be safe. I tend to use vanilla cells as a guide for how many to use. I think most people would rather forego pretty shadows in favor of better frame rates. But I almost always make a version of my mods for myself that has a larger number of shadowed lights because they just look better.

 

I don’t do console mods, but would have to assume that given their level of hardware they will have issues as well. The game engine just chokes on too many shadows under certain circumstances.

 

EDIT: Suffice it to say, that you can generally get away with more shadow casters in a small cell. That's why I refer to vanilla cells of a similar size to what I'm working on and go from there, erring on the side of caution if it's something I intend to share publicly.

[jojje5]

Thanks allot for your input RedRocket.

 

So if its an issue that can appear after time then i guess its a Vram issue. or more precise a Vram culling issue.

If that is true then its an issue that is unavoidable even if you so only have one shadow caster, the player just have to play long enough to run into it. limiting the number of shadow casters should increase the time the player can play before he needs to restart the game, but so should limiting the overall Vram load of the cell do as well.

 

Keep the overall Vram load of the cell low and you can get away with more shadow casting lights, and vice versa.

 

does that sound about right?

[MissingMeshTV]

Honestly, I wouldn't say its "unavoidable," maybe just less likely to happen...if that makes any sense. I don't think there is a single metric to use given there are so many variables in play (VRAM, scripts running in the background, etc. number of mods in use, etc). From my own experiences and from comments I've seen with major lighting overhauls (ELFX comes to mind) it ("it" being a slideshow upon loading into a cell) can sometimes happen almost right out of a fresh start of the game. It can be completely random. Limiting the number of shadow casters simply gives you better odds of not having issues. You can do a lot with smaller number of lights, but it might take a little more planning and experimenting to get the effect you want.

 

But yeah, keeping the VRAM load low might allow more shadows to be used, but then again, it might not in some cases...you have no way of knowing how one person's config is going to work compared to your own. The trick is to go with a happy medium.

 

EDIT: 1. Not singling out ELFX for anything derogatory and hope it didn't sound that way. It's a lighting overhaul I've frequently used and love, and one that some users seem to have issues with that I have never experienced. 2. I've also seen the lighting related "slideshow" occur in a number of FO4 live streams and Let's Play videos. I only mention it as background info to reinforce that it will randomly happen with no apparent patterns. I'm really not an expert, just blabbering from personal experience FWIW.

[jojje5]

well in a perfect world i guess it would be completely avoidable, but culling issues tends to have so many variables to them depending on system setup that i think its very unlikely.

 

I can elaborate a little bit more on what i think is going on if you like to get in deep, taken from my experience of modding other games.

 

most games are designed to cull Vram on scene change, some do a full purge of the Vram but most only does culling to keep load times fast, and the stress of the memory low. and as i understand so does fallout.

 

culling however has the drawback that it always keeps pieces behind that can eventually lead to bloat, and only with a perfect system setup where VRAM, RAM and HD works in perfect sync with no other processes disturbing it tends to work flawlessly. Now culling as the name suggest works by selective purging parts of the Vram rather than doing a full dump that is heavy and time consuming. and pieces that the system did not have time to purge in a designated time frame are put into que to get culled on the the next load, or they are kept around if the game thinks it may need them soon again. Here is where issues starts. this que system can get really messy depending on what system you have. (and a perfect system setup is not something that i think exists in the windows PC world)

 

and

in last few years with the introduction of SSD´s the problems with culling has actually gotten worse, some systems actually load faster than the time the GPU needs to cull the que. and one time in particular when this can leads to issues is when swapping between many other processes that hooks the GPU. like i for example think F4SE does,

and this is what i think happens when people report those totally random slideshows, they are not random at all. it was some other process that just messed up the culling que by inserting itself into it.

and this can ofc happen on any system it does not take much and you don´t need a SSD for it. but the problem can get significally worse with a fast HD and a slow GPU.

letting the system pagefile handle some of the que instead to give the system some more time to sort itself can often prevent allot of such issues, but in many cases it will eventually lead to bloating anyway and it is rather common that people does not have their pagefiles setup for that task, or they rather skip it because they think running without a pagefile will prolong the life of their SSD.

also not a good idea to rely to much on pagefiles if your HD is too slow.

 

then there is also ofc the age old issue of game developers on their quest for faster load times that takes shortcuts when it comes to culling, sometimes neglecting to assign a que priority to things that otherwise should be culled. (and sadly i think bethesda are among those developers who attempts shortcuts)

I have met game developers who thinks that if their game can run for more than a couple of hours without causing bloating that is perfectly fine. the average joe should not be playing longer than that anyways.

that thinking ofc just amplified the problems with the introduction of SSD´s and GPU clocks that are not designed to handle their short load times.

 

now lights and shaders in particular are something that usually has its own priority as the GPU reads that data often enough and tends to be culled last, so it is often a issue for bloating if the Vram never gets purged.

and it used to cause so much issues that NVIDEA and AMD has attempted to tackle the problem with their shader cache technology, removing most of that load from the GPU and placing it in its own dedicated cache.

unfortunately that rarely works out of the box and people have to go to their GPU control panel to set it up as NVIDEA and AMD is not really into collaboration.

 

so there.. i usually think like you Redrocket and like to go for a happy medium. but i am not sure where that is here.

some people who got a monster machine might get into severe culling problems by too many shadow casters, others who have setup their shader chache right might be able to run allot of them on a low end machine... so I kind of feel when it comes to PC modding maybe we could just wing it ?

Edited January 30, 2018 by jojje5

[chucksteel]

I play on both PC and XB1 and I've seen the wonderful slideshow effect even in vanilla cells like Ft Hagen after a 2-4 hours session on my Xbox. When it happens I just quit and reload and it's fine but, I agree just go with a happy medium with the shadow casters and your mod should work fairly well on console if you choose to share it with them.

[jojje5]

I play on both PC and XB1 and I've seen the wonderful slideshow effect even in vanilla cells like Ft Hagen after a 2-4 hours session on my Xbox. When it happens I just quit and reload and it's fine but, I agree just go with a happy medium with the shadow casters and your mod should work fairly well on console if you choose to share it with them.

that is pretty of interesting to hear that even Xbox vanilla can have those issues, it kind of reinforces my impression that the beth dev´s are taking shortcuts.

[payl0ad]

As a matter of fact, I can recommend Inside Jobs ( https://rd.nexusmods.com/fallout4/mods/27320 ) to you, we experimented heavily with shadowcasters. Move to the Quincy SD Mart by

 

coc tbQuincySDMart

 

Check out your frame rate while exploring the interior. On my dev machine it ran along at a smooth 45 fps, topping out around 5000 draw calls (ENB Profiler!). If you have many more, make sure Precombined Objects are on. That's a Core i7 4790 and a GTX980 on Win10.

 

Go down to the basement, remove the fusion core from the generator, then return to the shop floor. Removing the core disables all lights in the cell. Check your FPS. On my dev machine it topped out at 85 fps, same amount of draw calls.

 

That's one shadowcasting spotlight per light fixture, around 20 in total in the entire interior. Eats up half my frame rate.

[jojje5]

thanks allot Payload i will check it out :)

 

Speaking about Precombines by the way, that is something i cam currently toying with. and if the game indeed has Vram Culling issues then Precombines is something that should really help with that.

it goes allot faster to cull 16 objects merged into one from memory than it is to dump 16 individual objects, and the way culling works it might also be that only 8 out of those 16 objects gets culled in one pass and the other 8 remains if they are not merged as one.

 

so maybe this is something to consider when people are reporting slideshows in our mods. it could be that before they entered your cell they were in a cell with many individual objects or in a cell where the precombine system were broken.

[MissingMeshTV]

 

that is pretty of interesting to hear that even Xbox vanilla can have those issues, it kind of reinforces my impression that the beth dev´s are taking shortcuts.

 

The biggest shortcut being repeated applications of duct tape onto the same creaky, old game engine. :laugh:

But it can be said it is that creaky old game engine that allows Bethesda games to be so easily modded in the first place.