Unreal Engine 4 VXGI Quality at Close Range

In my earlier post on VXGI quality I kinda had a go at certain Evermotion scenes. That’s bad Karma of course. You always end up regretting things like that so to preëmpt such, I figured why not make a nice table arrangement with some content from their Unreal Engine 4 bundles, and show what a lovely collection of assets comes included.

So, what do a bowl of cherries, a green plant, some very odd-looking flowers and a bunch of vases and stuff, all arranged on a wooden table flanked by chairs that could either be some type of design furniture I’m unaware of or part of Ikea’ budget garden collection have in common? I have no idea. I basically loaded up Archinteriors for UE vol. 2 scene 1 and bunched up all small objects in that particular scene to create a nice little testbed for VXGI quality at very close range. Why bother you say? Well, why not? Surely it will come in handy at some point in the future to know whether VXGI can handle its own when in a tight spot where there’s no hiding for little render errors you might otherwise overlook. So, how did things pan out?

Scene setup

I used 2 spotlights for lighting. One is directly above the table. The other inside the table-lamp. Both have very narrow shadow bias settings to help combat the infamous ‘floating’ effect when rendering small objects in a dynamically lit environment. I got away with 0.01 without much shadow ‘moire’ but that’s mainly due to the overall scene size being so small. Material-wise there is room for a lot of improvement. Basically it’s just the default materials of the objects in the scene. Some look ok, some look very simple and others just look horrible. I could have improved many but ended up not bothering because 1) I just didn’t care enough 2) I figured it represented a nice ‘unpolished average’. Obviously point 2 served me just fine 🙂


Influence of VXGI on the scene’ diffuse is actually not that big. Yes there’s some nice subtle bounce light that helps realism but the biggest impact was from the specular pass. Unreal Engine’ Screen Space Reflections are helpful in some ways, but with a lot of objects spaced closely together, you often end up feeling they just don’t work properly. Specular cone tracing really enhanced a lot of the small gaps between objects while performing very stable. Last but not least comes occlusion. VXGI does a really good job here as usual. Object occlusion can even be seen between the smallest of spaces in the scene and scales up quite well for some of the wider shots.



I tend to put my Post-Processing settings inside my camera as opposed to running a global Post-Processing Volume. Somehow that made me run into 2 issues I am yet unsure off what causes them; Depth of Field produced very iffy results (so I ended up disabling it for all shots) and VXGI range is different from what I see when inside the editor. The latter in particular is most annoying since it forces you to guess part of what your final render is going to look like.  Probably my bad. I’m a noob. Sometimes I do things I shouldn’t do.


I used very high quality settings for VXGI. Needless to say performance suffers. For rendering a movie this is no issue whatsoever. Render time per frame was something like half a second.

Closing thoughts

For the next experiment I’ll probably switch back to Ray Traced Shadows from Distance Fields again. There’s quite some shadows in this clip I found lacking. I miss those nice soft shadows. As mentioned before, a bit of material enhancements would have done the overall outcome a lot of good and getting rid of the low-poly look on some objects wouldn’t have hurt either. Still, I’m quite content with the results I got. VXGI certainly didn’t disappoint!



Did I manage to leave out exactly the one thing you wanted to know? Wondering about something related to the above or just life in general? If you scroll down a bit there’s this handy comment section. Ask away and I promise I’ll do my utmost best to give you an answer you’ll never forget.


  1. Mork 21/11/2017 at 19:38 - Reply

    Great test! I’m practicing UE4 and VXGI a bit too and it does look very promising indeed.
    I’m experiencing some problems with:
    nvidia volumetric lights (1 direct light outside of a boxed room with some holes to come through…)
    they don’t show up no matter what i do..
    Depth of Field: it doesn’t work for me, i don’t know if it’s a general problem (i’m a total newbie to UE4) or if it’s for the VXGI configuration (i’m using https://github.com/MaximeDup/UnrealEngine/tree/4.17.X-GameWorks)
    Any hints?
    Thanks for your experiment, i found it useful!

  2. Anonymous 20/09/2017 at 15:48 - Reply

    What hardware were you running this on?

What do you think?

Send this to a friend