motion blur in post

#1

looking for a fast way to create motion blur, preferable in post.
doing a little search i found that mental ray motion blur is not on top, also it slows down my rendertime way to much.

so ether I could render out a motion blur pass using software render (2D motion blur)
or I could use this shader
http://www.alamaison.fr/3D/lm_2DMV/lm_2DMV_ref.htm
(hope tom_c compiles it for OSX : )
http://www.tomcowland.com/mentalray

does someone have experience with this shader or have any other suggestion how to get a quick rendering motion blur

thnx

#2

Salut Mimo
Recently I’m prefering rendering with MR then add some Motion Blur later in post. While I didnt make alamaison Shader work I still just use the nice utility from alias : blur2d.exe
Just render a second pass using Maya software and enable the 2D motion blur and Keep Motion vectors. You can disable anything that might slow down your rendering here, delete lights, assign a surface shader to the whole geometies disable raytracing …etc. Then use this pass as source for Motion vectors when blurng with blur2d.exe

Bonne chance.

PS: If it didnt work I’ll post later how to force it to work, I’ve written some notes somewhere in my computer the right steps , unfortunatly I’m on another computer right now.

#3

my problem with the blur2D.exe, I dont know where to find it.
couldnt grab it neither on the alias homepage, nor seeing it in the maya application (or extras) folder.

also I hope there is a OSX pendant.

thnx lazzhar old friend

#4

ok, I found this link, you run it like a batchrendering from the shell
http://caad.arch.ethz.ch/info/maya/manual/Utilities/blur2d.fm.html
will give it a try
sounds nice

still would prefer to be able to controll the blur in after effects, but this allready sounds promissing

#5

and now found this in maya help:

[I](Mac OS X) 2D motion blur is not supported in Maya for Mac OS X
Blur2D is a separate, stand-alone application that’s not available for Mac OS X.
Workaround

You can blur options in Render Globals while rendering.[/I]

so I will try to get this “alamaison” shader.

still trying to create a b/w image using a surface shader just on the moving object and then use this image as a compound blur source in AE … but that would be to easy

#6

I also realised that I would need the ReelSmart Motion Blur Plugg in to interpret the images resulting by using the alamaison shader.

still looking for a fast and free solution (doesnt have to be top notch)

#7

getting closer,
found the link to this page whith all the files for the installation of
lm2DMV_v2 for maya.

http://www.impresszio.hu/szabolcs/MentalRay/lm_2dmvMayaFiles.htm

even seems to have contain the OSX files, at least there is also a .so file inside.
but the rendering gets aborted:

mental ray for Maya 6
mental ray: version 3.3.1, 12 Mar 2004
Maya: Unable to dynamically load : /Applications/3D/Alias/maya6.0/Maya.app/Contents/lib/AvidOMF.so (0 2)LINK 0.0 error 191014: /Applications/3D/Alias/maya6.0/Maya.app/Contents/mentalray/lib/lm2DMV_v2.so: load failed, dyld: /Applications/3D/Alias/maya6.0/Maya.app/Contents/MacOS/Maya malformed library: /Applications/3D/Alias/maya6.0/Maya.app/Contents/mentalray/lib/lm2DMV_v2.so (not a Mach-O file, bad magic number)
LIB 0.0 info : mental ray for Maya - startup done
API 0.0 warn 302004: /Applications/3D/Alias/maya6.0/Maya.app/Contents/mentalray/include/lm2DMV_v2.mi, line 10: while defining declaration “lm2DMV_v2”: declaring nonexisting function lm2DMV_v2

did I write something wrong in the raryc (not the first time that i install a mr shader, allready have a hand full running) or is the .so file a linux version that doesnt help my mac.

thnx

#8

My friend Mimo, as I told you I didnt get success to make those shaders rendering Motion Vectors and I dont have access to t solution through Combustion(or AfterFX).
That’s why I stick with the blur2d wich is really good in what I’m after.
Her the steps to make it work. Dont stick on that, it’s just the first time I made it working so I noted all that:

Motion Bluring Rendering images

A- Render with Mental Ray without Motion Blur. Let’s say the rendered pictures would be: mr_myfile_beauty_pass.iff
B- Render a second time with Maya Software. This time to speed up the rendering, assign a simple Material like a Lambert or Surface Shader and delete everything that could slow down the render.
Enable 2D Motion Blur and check Keep Motion Vectors. This should force Maya Software to output the informationsbout the motion vectors and you’ll notice the the rendered files are big. I always get file size of 4 MB for a PAL format.
And let’s say our rendered out put would be: Maya_soft_myfile_MV_pass.iff
C- Render only to Maya .iff file format.
D- Make sure to not use any frame padding. So the correct format would be: myfile.iff.#
E- When you have all your rendering finished open a command line prompt then browse into there and use the utility Blur2d like that:

blur2d -l 2 -n 1 100 1 -f mr_myfile_beauty_pass.iff.# -v Maya_soft_myfile_MV_pass.iff.#

-l 2 : the blur ammount. I like to use 2, but try what fits to your needs.
-n 1 100 1 : The pictures are numbred from 1 to 100 by 1 step.

The process is not flexible, if you make a simple mistake you won’t get your results correct at all. If you can make it working save a template or something that you’ll use next times.

-lazhar

#9

thnx aggain lazzhar, but with all my postings you might have overseen that I found out that the blur2d function is one of the few options that maya on OSX doesnt have

in the meanwhile tom_c put a OSX version of the lm_2DMV shader on his page
http://www.tomcowland.com/mentalray/

thnx lazzhar and special thnx to tom … great support of the maya-mac community
:thumbsup:

#10

ok… check it out … i use ReelSmart Motion Blur 3.0 Vectors & lm_2dmv religiously when doing any animation in Maya/MR that requires moblur… here’s the steps to get it to work… the key to this … is … you must have a proper alpha channel … or your results are going to be completely wrong in the comp … here we go…

in your scene … create the lm_2dmv shader

drop it on every object in the scene (hide your lights, makes for faster rendering… as well as having raytracing OFF in MR)

go to your motion blur tab… and pop it open … set te motion blur to be on EXACT
go to the shutter attribute… give it a value of .01 … go to RGBA time contrasts attributes… set them all to the value of .01 as well

go down to the bottom of the render globals where it says CUSTOM ENTITIES … pop it open and click pass surface color to alpha channel … this shader by default… DOES NOT create an alpha, so to do this… this MUST be checked on, and this is what will make or break your motion blur …

in the lm_2dmv shader node … make sure you are set to ReelSmart Motion Blur Vectors … and i usually just leave the normalize value to 16 which is default …

hit render … pop it in the comp … drop it on the bottom or just hide it … apply the RSMB 3.0 Vectors filter to the layer … and then assign the motion vector pass as the source layer… and voila … you now have motion blur… (and be sure to premultiply the ALPHA on your motion vector pass)

hope this helps…

az

#11

Hi mimo8,

great thread, I was looking for something like this!
thanks!

#12

are there any limitations to using that MR post blur? I know with Maya’s 2d blur there are lots of limitations, like it goes not blur shadows, through transparency, no raytraced anything, cant blur very well with objects moving towards or away from the camera. Are all of these limitations present with this mental ray post process workflow?

#13

another intersting thing of note I must ask. I looked at the help section of blur2d.exe and there is no mention of a “-v” flag. I always thought that i could use motion vectors to blur other image sequences, but could never figure out how to do it. What is the -v flag?

#14

You have to remember… this is a blatant hack to get around the ridiculous render time of MR motion blur. You can’t expect it to be 100% accurately perfect. However, it is an extremely fast solution… With results that have been used in film. They look very very good. Yes, as long as you process an alpha… Your blur should be quite close, if not… the same… as to what MR punches out for you… When you’re in comp with it hooked up to RSMB 3.0 Vectors… It even processes the filter fast (depending on how crazy your comp is, I’m just going off of layer/source/result) … Either way… its saved hundreds of hours of waiting for me and other people here at work. As for blurring shadows? … You may be S.O.L. on that front unless you can think of a way to get it to spit out a SHADOW for the blur instead of a surface/etc… if you get what i mean …

oh, and it will not respect displacement mapping …

az

#15

I cant seem to get this to work in Digital Fusion using the ReelSmart Motion Blur v3 plugin. Im using Maya 6.5 and trying to use use the lm2DMV_v2 Mental Ray shader.

It renders fine within Maya, although it wont seem to render an alpha image (not sure if it is even needed), but the RGB seems to look ok. I then take it into fusion and try to work with the vector blurs and nothing happens. BUT when I put an alpha in there (channel boolean tha alpha from the beaty pass) then the blur works, but the blurs are wrong (i assume because of the worng alpha)

Has anyone had any luck with the shader and using it to blur in post, with or without Reelsmart Motion Blur?

Interesting thread guys, anything to speed up MR helps!

Thanks.

#16

read above to my first post, it explains how to force the rendered to generate an alpha. and yes, once again… an alpha is required for results… and using a track matte for an alpha doesn’t seem to do the trick… i’ve tried this myself in the past…

yes, I use it almost every day flawlessly.

az

#17

ooop!

sorry azshall (i hate people who dont read whole posts, looks like i’ve become one of em )

THANKS!

#18

Also, if 2D blur doesn’t give you what you need, have you tried the various motion blur options in mental ray?
Do you know how all this is linked to samples?

Have you adjusted time contrast, which is really just a way to specify number of time samples per sample?

Have you tried setting time contrast to all '0’s to use a faster motion blur, which depends on a fixed sample pattern, ie min samples = max samples? If your scene is filled with moving objects, this should make a big difference.

And if you don’t need raytracing, using the rasterizer (ex- rapid motion) is another faster option.

#19

Works a treat now, thanks!

One other quick question. Is using motion vectors a more accurate way to simulate motion blur in post over using Reel Smarts actual motion blur algorithms through comparing successive images?

Just wondering.

#20

what should be done with the general sampling and contrast values (should I use the same as I did for my regular rendered frames or is it ok to go with less quality here…)?