Maya, combustion and blur

[aaron_johnson]

i have a question for the combustion gurus out there who are compositing maya animations.

using maya IFF files (40 bit RGBAZ), if i do a blur operation in combustion will i get a good blur result for both maya and mental ray passes, and will the blur for different passes of the same animation match each other..? there's no way i know of to match blur results from the 2 different renderers, eg. if i render 2d blur from maya in a color pass, and any sort of blur from mental ray in say a shadow pass, they won't composite accurately. this leaves the only solution a compositor, so i need to find out if combustion is the package for me.

i know that at the very least combustion 3.02 is needed, because i heard on the combustion forums anything less will crash with IFF RGBAZ images. feedback greatly appreciated.

-paul

[user_deleted]

hey,
i am not a combustion guru, but i would say i trust more in shake for such things.
zBlurring in combustion works, but... how can you add/customize plug ins to combustion? If you are not happy with the limited standard set of tools, there is no workaround (outside of the after effect 4.1 SDK!!)
I would only recommend combustion to 3ds users... and shake to maya users

[aaron_johnson]

shake is not an option, it costs more than maya itself and i wouldn't have a use for 90% of the application's features. and its unsupported on windows, meaning i would have to buy a mac just for compositing.

i only need something to compile animations with what i would consider to be basic compositing features, Zdepth fog, blur, glows etc. all of which i would assume should be attainable in a US$1000 app, like combustion or AE. i have tested vegas and premiere, they are crap i've heard after effects doesn't really support maya's Zdepth data well.... but i hear so many different opinions its hard to know what to believe.

[user_deleted]

Combustion is a great soft, the bad point is that there is no way to customise it... Outside of the price, Digital fusion would probably match your needs, it includes a scripting language now, it runs under windows (and linux i think). That's an open environement.
Discreet is a reference but... I don't think discreet wants combustion to become too much competitive with their highend sgi/linux products (smoke flame etc..) that's the problem.
But, indeed, if the price is a problem for you and just need a basic tool for 2d/3d comp, go ahead with combustion it' works fine for what it have been made now.

[user_deleted]

this might interest you :
http://www.fxguide.com/fxtips-172.html

[aaron_johnson]

interesting read - thanks. so basically thanks to Alias's refusal to work on the IFF file format, compositing operations still don't work very well with combustion or after effects, and the workarounds are dodgy at best. but i guess they must have their reasons like consistancy for shake or something.

regarding the end of the article, i have been using blur2D in production for a while, unfortunately its not a solution for compositing when i have to combine it with renders from mental ray, which doesn't support motion vector renders and would calculate the blur differently (eg, if you overlay a blurred mental ray shadow pass over a maya color pass, they won't match).

hmmm... what i could do, using a Zdepth shader from within maya, is get a 'fake' Zdepth render that will result in a normal greyscale RGBA sequence... my question is would i be able to import that sequence into AE or combustion for that app to use as the Zdepth info....? because its an RGB render it would have the advantage of being anti-aliased as well, which maya's Zbuffer isn't by default

that might also solve the problem of compositing maya sequences with mental ray sequences as well.... but before buying combusiton i would still need to know that it would let me use a seperate sequence like that... here's hoping!

[devdoka]

Hi there,
Yes you can post blur your z depth in C*
Make sure you have the latest patch from Discreet
because there used to be a problem with iff and Z blur.
Now they have fixed it.
Actualy Alias hasnt refused to work on iff.
3rd parties dont invest more as they should.
And IFF in After FX works smooth.(at least thats what Alias says)
Mental Ray DOES support motion vectors.
There is a shader made from Guy Rabiller's.
You can apply this shader to your objects
Then use Reel Smart Motion Blur in Combustion.
Both After Effects and combustion can handle preety well
Z Depth.

All the Best,

-Dennis

[aaron_johnson]

mental ray _does not_ support motion vectors as maya does - its a fake method using shaders - i know of the one you mean.

AFAIK you wouldn't be able to match a blur with motion vectors done that way with a motion vector render from maya, because maya's motion vectors are not done with a shader, they're recorded into the IFF format.

technically Alias has refused to work on IFF, they're not a 3rd party - they invented Maya's IFF format (didn't they?) which would give them control over its development.

[user_deleted]

Sorry to be confusing but i think the article i sent you is out of date (pre 3.0.2). Now every package should basically do what you need indeed.
Maya's iff is the native format of shake. (so that's the natural way...)

[pierrejasmin]

FYI
http://www.alamaison.fr/3d/lm\_2DMV/lm\_2DMV.htm
see Horvatth Szabolcs' page for how to setup it up in Maya

Pierre
www.revisionfx.com

[george-stankevich]

--Double post--

[george-stankevich]

Blurring in post has always been the way

Whether you use Shake or Combustion is irrelevent, blur your layers (without their z) in whichever package and use the Z as an alpha for the blur.

Shake does have a specific Z-Blur but this is the work around.

Combustion also has a depth of field but its generally native to its RPF file format.

Oh, and to choose your depth, you solarize your z channel and invert it. So if your solarize is set to roughly 128rgb, (the middle) then everything either side of this becomes your blurred zone. Tweak contrast to widen/shallow this.

[aaron_johnson]

thanks for your post - sorry i took me so long to reply. hey that's a great idea about the blur method using Z as alpha.... hehe kinda obvious can't believe i didn't think of it probably cause i'm not used to good compositing apps that let you seperate out the channels of a sequence and do stuff with them

hmmm... actually is there a way to render Z only in mental ray or maya...? and/or any difference in the Zchannels between the 2 renderers?

thanks to all who replied.

[joojaa]

peronaly i dont use combustion but because theyr just passes of the same thing then they shoudl be all able to use the same z file because the objecst are the same.

BUt if there are a 2 different set of objects then you msut be abait carefull insisde amya and turhn of autoZ and set the depth to colsest visible (thats what mr uses).

if you just want the zbuffer from mr set the ramebuffer attributes dtataype to depth, or use any of the shders that conever dpeth to grayscale if thsts not your poison.