Vxgi Learning and testing experience sharing (from Unrealchina.alex_tsui)

Story to be from two weeks ago a big share of the panda Vxgi 4.12.2, after reading the PDF, I found a program colleague to help download the Vxgi 4.12.5 version of learning and testing on GitHub. Because it is the branch of Nvidia independent maintenance, there are not many examples of learning and reference. First share the test of the 4.6 version of Vxgi from the master's hand:
Https://www.youtube.com/watch?v=cH2_RkfStSk







Advantages:



Disadvantages:





I'm going to find this. Specifically discusses Vxgi's post study and research, the current two-year-long post has been 85 pages, the first 7 is about the physical simulation of the discussion, behind the basic every page on the VXGI real-time GI parameters and effects of discussion, see my snot a tear .... Finally did not remember too much, fortunately Netizen chariots summed up a bit. The following is the original text, my translation and test experience. All of the performance mentioned below represent performance, which can be understood as the smoothness of the screen or the friendliness of the graphics card. The better the performance, the more discounted the quality of the picture, the better the quality, the more sacrificing performance. Need to find a balance of your satisfaction. Just learn UE4 four months, there is no understanding and said the wrong place also ask you to forgive.

As Blakblt here, the default Vxgi settings seem to try to simulate the quality of the lights that have been built. This is good for architectural visualizations and smaller, more controllable scenarios, but may be problematic for other situations. You need a messy setup to achieve your ideal quality/performance ratio. The default values are in bold.
Alex Experience: The default parameters are indeed more intimate, but a lot of tonal deviation, need to add the LUT in PPV modified to achieve a satisfactory hue. (although I like the beauty of the 美图秀秀 bar ~ ~ ~) The default parameter how to tune. Look at this overview and this vxgi approximate algorithm.

Console command:
R.vxgi. Mapsize 32/64/128/256
Changes the size of the stereo pixel. The smaller (meaning larger stereoscopic pixels) the better the performance, but produces light leaks and inaccurate computations. 256 is not applicable to most of today's GPUs. Although Nvidia recommends using 64 for better performance, you can also set it to 32.
Alex Experience: If the video card is good enough, it is recommended to leave the default of 128, set to 64 to weaken the shadow generated by GI. Want to change the video card comrade tune to 256 play, Lu master second seconds alarm Letter ~ ~ Below is the comparison test 128:64




R.vxgi. Range 400
Change the range, as the name would be. However it has a border effect. If you increase the range, it also scales the dimensions of the stereo pixels, and the number of stereo pixels is a constant, so you won't get bogged down by too many stereoscopic pixels.
Alex Experience: Adjusting range values does not affect performance, I tested scene 300-400 is more suitable, low visibility range is small, the outer surface is black, that is, the above mentioned boundary effect. Range=0 the time of the crash, the range>400 of the GI shadow slowly fades until it disappears. range>5000 scene hue to the sun color close, gradually ignore skylight.

R.vxgi. Stacklevels 1/2/3/4/5
As Blakbit wrote in the post, setting it can have a huge impact on performance. VXGI reduces the stereo pixel resolution of the geometry far more than the VXGI anchor point (which is attached to the camera by default). The default setting has a different stereo pixel size of level 5. By reducing stacklevel values, you can increase (or decrease) performance. I suggest reading the post link above for more details. The main idea is that you need to find the best combination of values for your scene by using this setting combined with Mapsize and range settings.
In this post, it says that this parameter is less than 2 and produces a serious abnormal effect.
Alex experience: In fact, from 5 to 2, and did not find that the frame number is too obvious change, but the display range will slowly become shorter, the outer surface black. level=2 when the following image:

Level=1 the following image:


So I tried to increase the range, although the outer surface of the black faded, but the high range of the GI produced by the shadow also took away. While Mapsize remains the default of 128, increasing the video card is unbearable ... The following figure: level=2,range=3000,mapsize=128.

So personal feeling level and range generally can not move, there may be a better combination way I have not dug out.

R.vxgi. Multibounceenable 0/1
Enable multiple bounces, as the name suggests. According to the Nvidia overview, it works by using a glowing map of the previous frame at the current frame. Nvidia Overview here (required via GitHub): Disabling it will increase the performance of stereo pixels.
Alex Experience: The default is 0, off.
Disable:

Open:

After several bounces, the scene is slightly brighter and the number of frames is reduced. If possible, the video card is recommended to open, the following comparison chart is more obvious:




R.vxgi. Highqualityemittancedownsamplingenable 0/1
-----Daniel.wenograd Posts and vxgi at a glance are mentioned in the following two links.
Alex's experience: I'm a DJ. mentioned, it is really just mentioned, a little more explanation is not. Just saying keep the default off can improve stereoscopic pixel performance. So I tested it, the following diagram remains the default is not turned on:

The following diagram opens:

Personally feel that there is only a little difference between the naked eye, the darker part of the light, not very obvious. Reduced frame count. However, there are few lights and no spontaneous light objects in this scene, so we need to test them further.

R.vxgi. Storeemittanceinhdrformat 0/