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Libor
01-06-2009, 03:15 PM
Hi there!

Im just messing with new render passes and I couldnt get working motion vectors :sad:

Yes I know the way how one get passes rendered out but the motionvector frames seems screwed up! when I flip the image sequence its blinking like hell and also doesnt look like mvector pass but fancy rainbow :(

The bad thing is there is actually not any info about this in manual! Just a note about type of this pass....

There is also several nodes containing word "mvector" do anybody know which one to use in Nuke' s vectorBlur node?

Is there any special workflow for correct output of mvectors like before in older maya versions (turning mblur on but setting zero in amount etc.) or one dont need to bother with special render global settings....


Thanks to anybody for insight in this topic!

L.

jande
01-06-2009, 06:05 PM
I found the remapped/normalized ones useful in nuke. at least nuke didn't produce that much artifacts as it tends to do.. of course you have to boost/tweak them... but the other ones were fine too. MVs are the only thing I could get to work as expected using the new renderpasses in M2009.. besides that I'm still baffled about the all the other ones.. but might be just me.... the whole framebuffer annoys me. ' figured out that once switched to .exr output the render passes are not displayed in maya as they do in nuke... are you viewing your MVs in Nuke or in Maya?

haven't checked all that pass stuff yet and still trying to grasp. would be interested in some in-depth thoughts about that topic too

Libor
01-07-2009, 09:09 AM
thx Jande for response!

Are you using mvector just with exr format or even in other formats like 16bit Tiff? As I can see the only format for this pass is 32bit float (Render Pass Attributes window) which probably causes that one cant use other file formats...

Maybe thats the problem I cant solve....

Could you give me short info about using it in Nuke with vectorBlur node? It accepts u and v channels (forward / backward) but how the hell one could connect these?!

Thanks again for your time!

L.

Libor
01-07-2009, 10:44 AM
Ok, I have found this great article about using mvectors in maya (http://aloedesign.com/2008/12/maya-2d-motion-vectors-tutorial/).

Followed it and even succesfuly connected vectorBlur in Nuke but...

it seems that last problem is in the mvector pass itself!

It seems, that all objects even those static got the same color (yellow green). Only background has grey color which mean no movement...

its really strange :(

Im using exr format (tried different bit depths like 16bit / 32 bit float) but still looks the same.

Anybody any ideas?

thx

jande
01-07-2009, 11:32 AM
mhmm.. have you mesured those yellow green values? since its float it may have some values above 1 or below 0... but I could build an example and post it here..

ahh.. and yes I'm trying to use exr only, usually 16bit half float.. hang on a sec and i'll post an example... (in case you're not using multichannel files you have to shuffle the vectors into the image you want to blur, but I guess you have done so already)
cheers, J.

EDIT: MVs should be float... but 16bit should work with this RSMB gizmo at fxshare.com (i suppose... haven't tested yet)

jande
01-07-2009, 12:42 PM
in case you still having trouble.... hope that brings some light into the dark.
let me know if you're still having trouble or need the source files.....

so: MVs have to be float! (don't know whether is a big difference between full and half)
DON'T view ur passes in maya when outputting EXR... hope its just me, but the passes appear different in maya.. view them in nuke and you'll see what you really have. the way maya handles those passes in the framebuffer is just crap. so to contradict myself.. don't use the normalized MVs
If your Geo is simple check out nukes ability to make motion blur by using the geo and the cam. (although this takes ONLY the cam movement into account, but looks nice!)

hope that helps. let me know if you're still having trouble
cheers, J.

(sorry for the bad jpg due to upload limit, hope you can read the stuff, nuke file is pasted below, but you have to make sure your input channels have the same name if you wanna use it... but its easily set up so forget about)




set cut_paste_input [stack 0]
version 5.1200
push $cut_paste_input
Premult {
name Premult1
selected true
xpos 79
ypos 86
disable true
}
set Ndba85d8 [stack 0]
add_layer {MV2E_mv2DToxik_persp MV2E_mv2DToxik_persp.X MV2E_mv2DToxik_persp.Y MV2E_mv2DToxik_persp.Z}
VectorBlur {
channels rgba
uv MV2E_mv2DToxik_persp
scale 2.4
method forward
alpha rgba.alpha
name VectorBlur1
label "USING JUST PLAIN 2D MV\nNAME OF THE PASS IN MAYA after ASSIGNING IT\nIS MV2DToxik !THIS IS THE ONE YOU SHOULD GO FOR!"
selected true
xpos -60
ypos 141
}
push $Ndba85d8
add_layer {MV2N_mv2DNormRemap_persp MV2N_mv2DNormRemap_persp.X MV2N_mv2DNormRemap_persp.Y MV2N_mv2DNormRemap_persp.Z}
VectorBlur {
channels rgba
uv MV2N_mv2DNormRemap_persp
scale 28
method forward
alpha rgba.alpha
name VectorBlur2
label "THIS ONE IS THE NORMALIZED MV\nITS RUBBISH!... THE SCREEN LEFT SPHERE HAS ONLY Z\nMOVEMENT, WHICH SEEMS TO GET SCREWED UP"
selected true
xpos 225
ypos 140
}

Libor
01-07-2009, 04:48 PM
jande thanks again for your kind interest into this problem!

I finally solved my problems with a big help from you!

My conclusion is:

1) setup output from Maya to .exr (RGBA 32-bit float)
2) use 2dmvToxic pass
3) in post use vectorBlur nuke node with settings (offset u=0, v=0) and appropriate channel (2dmvToxic) and multiply factor as one wish for blurring it all

It all works together now! :beer:


PS: Sorry for not posting any imgs but unfortunatelly I dont remember now my ftp password:rolleyes:


Cheers mate!

L.

jande
01-07-2009, 04:56 PM
no worries, you're welcome

regarding your conclusion (I should have written like that =) ) I don't think one HAVE to render full float... in my example half float just did the trick and saves some diskspace
cheers,
Jan

highpoly
11-01-2009, 08:38 PM
Hello, I am trying to use the Normaized pass for MV in mental ray but I am not seeing this

"2dmvToxic" that Libor spoke of. can someone please help with this process? i cant seem to get right vectors out of maya or readable in NUKE. really not understanding what doing wrong

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