Motion blur, and particles

[mrpotato]

Hi everybody!

Ive got a big headache with MAYA motion blur (surprise,surprise...) ive got a shot of a car with its rear wheel sppining like mad, ive created a proper particle system simulating the friction of the wheels and the floor,ok when i render a frame everything is fine, the problem comes when i start playing with Motion blur in the shot... I dont care about having motion blur on the particles, what annoys me is that when i activate the motion blur option the render of the particles is very different, they are much more darker, less trnsparent, they look more dense and worst of all, there appears ramdomly some more particles in some frames making a very annoying popping effect... the problesm dont end there, 2d motion blur doesnt work so bad,and 3d blur is a no way (it takes ages and too much memory...) Ive read many post saying the best solution is composite everything in postprodution, ok my problem are, the wheel spins very fast,but because the tire is very dark, when moving only the alloys seem to spin, so im not sure if the motion blur of the postproduction software will work the same with the alloy and with the tyre... anyway, how many passes will i need to make the composition?is it really posible to do in different pases and combine them??? bear in mind the camera angle has a lot perspective and particles are surrounding all the tyre....
I personally think the best solution will be 2Dmotionblur Of maya, but is there anyway of getting out those pop up particles, could they be happening beacuse the particles arent BAKED? if so how can i BAKE particles (i know how to bake objects,but not particles.. ) ive tried using cache, but the resoults are exactly the same...

Anyway i dont wanna make more questions, i think ive created the post whith more questions per sentence of all highend3d XD sorry about that, just wanna know if there is a solution for all this apart from suicide...

Thanks a lot for ur time,its reallya shame having a nice shot done and start having problems all this problems just by activating the magic MAYA "motion bluuur"ALIAS WATCH UR RENDERER!! (im using maya 4 by the way....)

[deke-kincaid]

Your problem is a known limitation since Maya 1.0.
Look in the release notes for Motion Blur:

General Motion Blur Limitations:
Motion Blur does not work with particles.

This limitation is only for software particles, you can motion blur hardware particles and composite them later as long as your video card supports it(alot of cards don't support this). Otherwise your going to have to render the software particles in a separate layer and 2d blur them in post.

Deke

[tokyostormdrain]

Deke's right about the motion blur. I found it out the hard way too, even had to post a similar (albeit shorter) question here as well! : )

But as for your popping particles, bake's not a solution. Just make sure you've cached your particles. It should be in your [Dynamics] Solvers -> Create Particle Disk Cache menu...

At least that's where it is in 3.0

Running this will allow you to cache your particles, which means they'll run the same way every time you play in your time slider, plus you can scrub your animation and the particles will remember where they belong and go there. I'd like to say it's flawless, but it's not (it's Maya : )) so outcomes will vary but it should work.

Good luck.

-FS_RAZ

[mrpotato]

In reply to:
Your problem is a known limitation since Maya 1.0.
Look in the release notes for Motion Blur:

General Motion Blur Limitations:
Motion Blur does not work with particles.

Yes i know that, but im not looking for blurring particles, i just wanna blur the rest of the object, im just expecting the same results in the particles as if i dont use no motion blur basicly i want: particles (without motion blur)+motion blur on the rest of the scene objects - no problems with poping and darkness of the particles ,is this asking so much Alias???

Ive cached too the particles i thought that could be the reason for the poping, but they still appear im going a bit mad here... i think many of my shots wont have particles... is gooood to have so many tools for making nice particle animation and not being able to show them... sorry guys but im a bit pissed with all this

Thx anyway

[bosco]

Have you tried rendering the scene with motion blur and no particles, then rendering the scene with particles and no motion blur, with a useBackgroundShader on all the geometry, then compositing it? You don't have to do the motion blur in post, you only would if you want the particles to m.blur, which it sounds like you don't.

I know, I know... I hate the pat answer, "composite it" as much as anyone. By now some of these problems seem pretty basic, and you'd think they'd be fixed. Only time will tell...