More Light

[Gunnah]

Hilo,

In the vray docs it's mentioned that mesh lights do not behave correctly if motion blur is enabled on the objects, and that it will be implemented at a later date. Is there a rough estimate when that later date may be?

cheers in advance

cp

[Gunnah]

I should also mention, this is also the case with vrayLightMTL with "direct lighting" mode enabled. So I'm guessing internally the "direct mode" just creates a vray light object for the direct light for the objects that lightMTL are assigned to?

[^Lele^]

The docs may contain a refuse: both the mesh lights and the light material with direct lighting seem to work just fine for me, what issues do they give you?

[Gunnah]

Hey Lele!

1. create a teapot, a vraycamera and a plane under teapot
2. create a Vraylight and make it a mesh light and disable replace object, then click the teapot
3. parent everything to the plane
4. animate the plane from origin to 50k units away over 25 frames
5. render on any frame in that 25 frames, and it renders fine
6. turn motion blur on the camera now
7. render again and result (in those 25 moving frames) will be no light from the meshlight unless you enable GI (and even when thats enabled its incorrect) anything *outside* that range should render correctly as well.
8. now apply a vrayLightMTL with "direct" option enabled to the teapot, turn off the meshlight
9. render again and result should be same as meshlight when in area things are moving and moblur is enabled. (GI will behave the same way as well)

I know this might be an edge case, but I can repro this on a bunch of machines.
also this isn't the only way to repro it either, it seems to happen with pointcaches and modifier deforming geo as well, but gives a REALLY crazy result.

hope you can repro as well lol

cheers dude

CP

[^Lele^]

Hey Chris!
Well, i have a bit of good, and a bit of bad news.
The bad news is i can't repro (see attached.), the good news is that maybe it's the latest stable nightly being better at it (on top of having the new bucket splitting algo!).
Would you mind giving that a whirl?

cheers yourself!

[Gunnah]

Will do, thanks for checking (stupid me, I should have mentioned this was 2020 and vray 4.30.03 build 30575) I'll try in 5 but I don't think that'll help on the show since we can't switch, but at least we'll know if that fixes it in any case.

I'll let you know if that does indeed work tho

cheers again dude

[^Lele^]

Ah!
I'll poke the devs and ask for directions, will PM you as i'll know something.

[Gunnah]

ok so just checked my file in 2020 with vray5 update 2.2 and its still not working there. I'm going to get the IT guys to send you a scene file to take a peek at. (i'll get them to CC you on the email)

[^Lele^]

That was quick!
thanks, i'll be waiting.

[Gunnah]

haha just had to change configs

[^Lele^]

Chris, i was made to notice that indeed you are right: the light *flux* isn't motion blurred (as visible in my own tests, when one knows what to look for, which i didn't.).
We have this in the list of bugs, will bump its priority.

EDIT: An instant fix to the specific issue is achievable by exporting to vrscene and rendering with standalone. Be warned that not all the features of native Max may be supported, though. A dedicated pass is likely the lesser headache.

[Gunnah]

Haha thanks my friend

I finally got them to send a file to you just in case you need another repro case


cheers dude!

cp

ps: I'll try it in the standalone when i have a sec