View Full Version : hypervoxel particle blur and refraction - MB not working

12-15-2012, 05:27 PM
hey all,

using LW11

cant get my hypervoxels to blur ...
i have a moving emitter firing partilces sized to the voxels attached to them that represent "heat" from a jet ( ie: not "point" sized particles ), it also has some "dirty" sprites emitted from a clone of the voxel emitter, to create a slightly dirty jet exhaust plume. everything else in the scene blurs beautifully except the voxels and the sprites, regardless of how i change settings for blurring.
-particles not calculated! (if i calc them they all bunch up at each frame, no idea why and it looks stoopid, so i let em go free)

my render settings are;
shading and light sampling set > (tried 2,1) *(tried = no avail.)
cam AS min samples > 1
cam AS max samples > 2 (tried 4)
MB photoreal (tried the others as well (usually use classic))
MB length > 100% (tried <100%)
MB passes > 4

a suggestion i found was to replace the particles with null's as MB dont work with particles ( certainly those that are essentially 0 in size (points), mine are not ). this seems to make sense, however it was pointed out that you would get a huge number of nulls to deal with. my "jet exhaust" is one of 6, so i could end up with 15 odd thousand nulls by the end of the scene. prolly too many to deal with ...
another suggestoin was to enable VectorBlur i the scene window(?), not sure quite what they meant but from the description it seemed logical enough. if anyone has got this to work id love to know about it.
failing that i was wondering if there is also a way to do a quasi-MB 'pass', as MB is dependant on object-camera movement(?), ie: i render to stills, then render stills to anim (this way i can start/stop anywhere during a shot if i have to). is there a trick that could be used to "tween" the frames when rendering a still sequence so as to gvie the impression of bluring in the outputted animation?

now the other problem is the refraction of the voxels to give the heat look "cuts" the "dirty" sprites along the voxel edges (where refraction is high presumably). i originally had the voxels tinted to look dirty but just looked like smoked glass (crap), so i added (cloned emitter) sprites to the plume and i looked much more like a real jet exhust plume.
so is there a way to exclude the sprites from being effected by the refaction of the voxels?
rendering a sample now and will post it.



12-15-2012, 05:33 PM

heres a sample of the shot (small bit = short render. soz, u prolly wanna save it as and then zoom in a bit.)

everything photoreal bluring, except the voxels and sprites. * note the hard edges where the voxels chop up the sprites. admittidly if the MB was working on the particles it would prolly look fine , but ...

12-15-2012, 06:24 PM
try to set up a clean scene, just one emitter firing upwards hypervoxels. They do blur, at least in 10.1. If they dont then it is a bug.

12-15-2012, 06:42 PM
ta for the reply mate, i shall give it a go.
VectorBlur didnt do anything to help as far as rendering stills>anim, that i could see (stills being a backdrop sequence).

12-15-2012, 07:44 PM

simple scene: 1 static emitter firing up separated voxels = blurs beautifully.

my complex scene with only 1 moving emitter firing down = no blur at all.

same camera, render, emitter and voxel settings (as far as i can tell).

anyone know why this might be happening? got me stumped!


12-16-2012, 03:22 AM
Must be some bug bro, because I just tested on my crappy laptop with LW96 and it blurs downward as well.
So you can report it along with your scene to the debugger guys. I guess.

12-16-2012, 09:37 AM
HV blur doesn't "work" with 1 pass motion blur, especially Photoreal mode. Must have multiple MB passes.

This remains annoyingly peculiar since particles with Instanced objects blur just fine with 1 pass PRMB as both are volumetrically rendered.

12-16-2012, 11:03 PM
LaughingJack & bazsa73, when you describe getting MB from HVs, are you referring to them working with 1-pass PRMB or with LW's "legacy" multi-pass MB? Put another way, is your MB (that is "working on HVs") set to use more than one pass?

I'd love to hear someone from Newtek conclusively state which volumetric fx (should) work with PRMB and/or "legacy" MB in LW11+. It's getting quite difficult to distinguish pathology from "known incompatibility" at this point, since so many seem to have differing results in terms of what works with PRMB, what works with legacy MB, etc.

12-17-2012, 03:11 AM
ta for the replies guys.

@chrusion, im using 4 passes regardless of type of MB. im also assuming that because the "particleBlur" button is a 'toggle', that the particle blur is also 4 passes....?

@jwiede, i have tried Classic, Dithered and PhotoReal, MotionBlur, all set to 4 passes as this seems to work for all but HV's/sprites(?), and it loks good enough for what i want. i have tried using 7 passes but that didnt work either. ... just thinking about what you said, do you mean that PhotoReal-MB is only a 1 pass operation, independant of the selected number of passes?
as to your second para., i agree, im only a hobbyist and ive been stumbling around this minefield of voxels for sooo long. there is not enough info in the docs about how to actually Use the tools in Lightwave, just what they do (?). ive learnt myself pretty much most things by trying and fiddling over the years and i can do a lot, but some things just elude me about how to properly "Use" the tool. HyperVoxels is one and using Nodes is the other, E'gads! Nodes are tricksy...!

... i used a "fresh" emitter in the test that i did (firing up), with 4 passes (all settings same as my other scene) and it worked. would that then suggest i might have to replace my emitters with new ones and re-setup the HV's ?
BTW in that test i also did a still shot with the emitter moving away from the direction of fire and it also blurred properly. so a moving emitter does not seem to be the problem either.

12-17-2012, 04:40 AM
LaughingJack & bazsa73, when you describe getting MB from HVs, are you referring to them working with 1-pass PRMB or with LW's "legacy" multi-pass MB? Put another way, is your MB (that is "working on HVs") set to use more than one pass?

I'd love to hear someone from Newtek conclusively state which volumetric fx (should) work with PRMB and/or "legacy" MB in LW11+. It's getting quite difficult to distinguish pathology from "known incompatibility" at this point, since so many seem to have differing results in terms of what works with PRMB, what works with legacy MB, etc.

Indeed I forgot to mention the fact that I did use multiple photoreal motion blur passes.

- - - Updated - - -

What if your particles are just way too slow to produce considerable motion blur? But multipass photoreal blur is not a one pass operation, and it should work. I guess it's
a bug in LW11 if it doesnt work. Why dont you share the scene without the geometry and all. I would like to have a look at it.

12-17-2012, 04:52 PM
Um, might be mistaken, but I thought the act of setting passes to >1 disabled "Photo-Real Motion Blur" (PRMB) and instead uses "Legacy Motion Blur".

12-17-2012, 05:19 PM
@jwiede - I don't think setting passes to >1 disables PRMB. It just does smaller sections of PRMB to go with the smaller time slices made by setting higher passes.

@LaughingJack - I think Particle Blur is for 1pt polygon, or "partigon" emmiters. It turns them into streaks instead of dots.

12-17-2012, 09:33 PM
Unless it's changed recently - particles don't exist between frames, so the particle blur toggle is really necessary to blur any particle based stuff.

12-18-2012, 01:56 AM
thanks again for the replies :-)

done some testing with a new emitter (not a clone), beside the original and got this...


L/H = orig. R/H = new emitter

no blur on the new emitter, so maybe its a scene-thing ? ... and just twigged that anti-aliasing is not working within the volume of the HV's, so something is really screwy.

ill bundle the scene, minus the ship object, and post it when i get a chance. chrissy holidays and all that...



12-18-2012, 02:48 AM
You have to switch on volumetric antialiasing! I just tested. If off, no blur nothinh big nada. So check on Effects panel / Volumetric tab (^F6)

12-18-2012, 01:18 PM
You have to switch on volumetric antialiasing! I just tested. If off, no blur nothinh big nada. So check on Effects panel / Volumetric tab (^F6)
That didn't affect motion blur too, did it?

12-18-2012, 03:29 PM
I ran into this on a project last year in 10.1 and I've submitted bugs for it. The problem is if you use particles and hypervoxels, the only way to motion blur them properly is upping the passes (to ridiculous levels if they're moving fast and near the camera). So you have these crazy-long 30-pass dithered-motion blur renders in order to get that non-stepped, natural photo-real motion blur look. And HVs don't show up in the motion buffers, so no motion blurring in post. It's makes doing rain/snow/hail (stuff that's near the camera) really hard and have excessively long renders. The dev team knows all this too.

And yes it doesn't make sense that instances motion blur fine and show up in motion vectors, yet hypervoxels don't. They're both volume plugins. :screwy:

12-18-2012, 04:15 PM
It did, no mblur if volAA is off. I think mblur and AA are connected, at least photoreal MB is for sure. That is kind of an AA blender.

12-24-2012, 07:46 PM
Ta for the replies. :-)
So, volumeAA makes the diff then? Hmm, had it off to reduce render times... Ah well ill flick it on again, see how it goes. Seems wierd tho that it makes the blur work... Will try it after I get back from chrissy holidays, in QLD atm, on phone wi dodgy reception :-/

12-25-2012, 03:10 AM
@ evolross, i tried with 7 passes and still got zero MB, not stepped or rough, but zero. and i aint gunna be doing 30-odd pass renders either as i dont have a renderfarm at home. also, are instances not just "objects" rather than "shaded volumes", and that is why they MB-render but not HV's? ... i have no idea so some clarity would be nice. :-)

will be trying bazsa's idea when i get home, see how it goes.


01-11-2013, 09:53 PM
hey all, happy new year!
well Bazsa73, you be right and thanks heaps! :)

Volumetric Antialising IS required to achieve blurred Particles, regardless of motion or MB settings. This suggests that the 'normal' AA works on everything except volumes, even if they are moving (multipass MB), lightwave simply ignores any Volumetrics when running Normal AA passes unless Vol AA is turned -ON.
The wierd thing is that Particle Motion Blur will not work unless the seemingly unrelated Vol AA is activated

some pics here to show the changes using different settings

110354 <- MB -ON (classic), Part Blur -ON, Vol AA -OFF
110355 <- MB -ON (classic), Part Blur -ON, Vol AA -ON
110356 <- MB -ON (PhReal), Part Blur -ON, Vol AA -ON
110357 <- MB -OFF, Part Blur -ON, Vol AA -ON

one thing i noticed was the lack of relatively visual difference between Classic (3.9 sec) and PhotoReal (4 sec), exept for the render times.
the other was that without any motion blur passes, Particle Blur seems to only blur (smooth?) the surface of the particles (with VolAA -ON)

thanks again everyone :)


ps; when it finishes re-rendering this shot again ill upload it and post a link.

01-12-2013, 10:11 AM
Still though, single-pass photoreal motion blur does not work on particles no matter what. You have to up the passes and then it's still only dithered motion blur. Not the photoreal algorithm.

Bugs have been reported.


01-12-2013, 10:01 PM
hi evolross,
i used 4 passes for all the tests (my default) and both Classic ans Photoreal worked fine and i cant see much real difference.
would you not have to run more than just a single pass to get any "motion"? dont know exacly how photoreal works, so if you could enlighten me id appreciate it :)



01-13-2013, 04:49 PM
There is a big difference between photoreal and classic motion blur. Classic has a stepped look that's based on the number of passes. Photoreal has a more natural dithering/blending and can be done with fewer passes than classic. Yes, if you up the classic passes enough you'll get a good result. Upping the passes on photoreal helps too, but you can use 1 pass if you'd like.

For high-end visual effects work, you have to use photoreal. Classic looks fake and stepped. (SIDE NOTE: before Lightwave came out with photoreal motion blur, you could always spot Lightwave renders in movies and TV shows because it was one of the last major 3D software programs to not have photoreal motion blur. You can actually see it in some shots in Iron Sky too, especially with the particles. You'll see that stepped motion blur look.)

So in my render above, I'm illustrating that photoreal doesn't work on particles, which was the point of my original post which is to get good motion blur particles you have to go to really high number of passes, especially if they move close to the camera, else they'll look stepped and bad. I actually recommend doing motion blur in post, but you can't with hypervoxels because they don't show up in the motion buffers of Lightwave.

01-15-2013, 03:47 AM
ah, i see now, thanks for the info. was going to use particles to create a 'tracer' type ammo coming from a machine gun later, so ill keep all that in mind. :)

thanks again



ps: rendering this shot (230frames) will take a while. so far, without any HVs on screen, im at 1hr17m per frame :/

01-17-2013, 05:17 PM
just re-reading all this and i realised in my post #21 that my opening line should have been,
"Volumetric Antialising IS required to achieve blurred Volumes, regardless of motion or MB settings",
not "blurred Particles". sorry bout that but there is a diffenence btween 'Particles' and 'Volumes (volumetrics)', especially with relation to everyones discussions here. my bad :foreheads


01-17-2013, 05:26 PM
sorry - lost track - did you resolve this problem? Looks like you're using particles to mimic hot exhaust? There are ways to do it without particles - or volumes

01-19-2013, 08:13 PM
hey toby,

yeh ive fixed the problem for the look and quality i like, and want to bother with :)

hot exhaust is exactly it. ive used volumetrics for both the Heat (Surfaces) and the Smog (Sprites). its the closest i can get with my limited knowlege and its taken far too long to get it to look right (same with the clouds).
one shot i wanted(still want?) to do was the camera pointing at the main engines as they cranked-up, while flying the camera through the plumes. the problem i found is that "blended" volumes gives only a skin of surface (theyre not solid), so no messed up blurred effect going through the plume, just looks like an animated hollow glassy tube. to fix this i need to "un-blend" the volumes but this takes waayy longer to render, hence my reluctance to do this shot.
if there are other ways are there to get this effect i would love to hear about it. :)



01-19-2013, 09:37 PM
Oh you don't want to run a camera through volumetrics!! Unless you want your grandkids to finish the project for you :yoda:
But you could try using a volumetric light instead. If it's the distortion you want, render a matte with the volumes and distort in post. If you do that, you'll want to render overscan (larger image but only to render a larger area) so that distorting it won't bring in black from outside the frame.

01-23-2013, 12:11 AM
lols toby, yer right. i think from memory it was taking something like 20+ hrs rendering a frame and that was only part way through!! :).
I have done the shot before the one im currently doing and that was flying in through a cloud bank i made from HVs and i found 2 things that forced me to fly the camera Past bits of cloud rather than Through them.
the first was that when i got really close to the cloud it would become grainy so to compensate i thought i could turn on NearClipping for the HVs (set it for 1 km as smaller lengths seemed to be A cause for the 'scalloping' problem (below)). this however caused some of the HVs to clip out while they were still in frame... looks a bit silly.
the second problem, and i got this a little bit with the exhaust but because its blurred i dont show up so much, was that when i got really close to the HVs and (maybe?) they were overlapping or i was passing through an intersection of HVs?, there would appear to be scalloped out sections on them, a rendering error i guess. so ive tried to avoid as much as posible going through HVs, not only because it takes ages to render but more importantly because visually it ends up not having artfacts if i do this.
ive never played around with Mattes or rendering passes that only do certain bits. heard about people doing this or that rendering pass and then 'putting it together' in Post, but ive never truly understood the reasoning or methods of doing these types of renders and therefore never tried it out. been trying to get a hold of some more vid tutes (theyre awesome by the way... guys what make em :) ), and been trying to find some downloadable books etc that people have done that actually show you how to use the tools. as ive said before the manuals for lightwave only describe what the tools do, not how to actually use them. i have an old Alban 'Power Guide' from LW4, but thats so out of date now i hardly look at it.

thaks for the replies



ps; currently scene @ 20% done averaging 2Hrs/frame, elapsed time 58+Hrs, remaining time 255+Hrs. heheh ;)


01-23-2013, 12:44 AM
Buy a second-hand 8-core, do your renders, then sell it again for nearly the same price! That's what I might do - or I'll be stuck rendering for, at least, 4 months straight.

Wait, 255hrs is only 10-11 more days - you got it easy my man

01-23-2013, 06:27 AM
Agreed with toby, just try somehow to fix it in post with minial effort. The brute force straight into the volumetric fog means you stuck in the timewarp.