View Full Version : 3d compositing.

04 April 2005, 04:17 AM
I rendered out some passes = diffuse, specular, reflection, noise/dirt/grime, occlusion, ambient, beauty, fog, lights, dots for tracking lens flares, Z-depth.

I am new to compositing.How do i composite it in after effects.I have 6.5 pro.
Using alpha chanel ?multiply layer?

thanx for helping.

04 April 2005, 08:59 AM
As a matter of interest, what 3d package are you using. I would like to know how to do this easier than I do now in Lightwave.

Anyway, try this link. It is a Lightwave setup, but the last column I think is the After Effects setup details.

Hope this helps.

04 April 2005, 08:36 AM
I plan to use After Effects.
The guide is usefull. Is the layer arrange from up to down in the guide?

Many term such as differences or screen I do not quite understand.

Thanks anyway.

04 April 2005, 08:32 AM
Sorry, I meant which 3D package did you render out the files.

As for the layers, when you add one of the passes as a layer, immediateley to the right of the name of the layer, is the mode button. Press this to change the blending type. I do not know what order they should go in and plan to mess about with it myself.

Let me know if this helps at all.

04 April 2005, 09:37 AM
I uses maya.
I tested AE.Cool, still exploring.
If you could figure out the layer composition in order from up to down.Please gimme some tips.

04 April 2005, 05:53 AM
This is how I would comp it from lowest level to top:

layer type: transfer mode
beauty: normal
diffuse: normal (with transparency to adjust the beauty)
occlusion: multiply
ambient: add (or screen) (can be used to add slight ambience lighting)
specular: add (or screen) (can be used to create specular blooming)
reflection: add (or screen)
noise/dirt/grime: depends on the image, but normal or multiplied
fog: depends on the image, but I use lighten to give atmosphere
lights: add
dots for tracking lens flares: screen on top after tracking & applying the flare

Z-depth: used to control effects like depth of field, faking atmospheric fog, depth queing, etc.

There is no hard rule on how to layer the renders, and most layers will have some sort of transparency. Any layer can be used for a variety of effects, for example, normals can be used to "key" X,Y,Z direction in comps, fog can be created from a depth render, dirt and grime can be used to matte out reflection layers or even multipled on a reflection layer to take away reflectivity, and on and on. Just watch for color clipping (usually from adding too much), check your histograms, use reference material for lighting, and have a good eye for detail. Hope this helps.

BTW, if you're interested in the techy side of comping, I highly reccomend The Art and Science of compositing (or something like that) by Brinkmann.

04 April 2005, 06:12 AM
Thanks dwkim.:thumbsup:

One more question.
Whats the different between occlusion and ambient and their purposes?

04 April 2005, 12:54 AM
I use occlusion passes to darken those nooks and crannies where light doesn't hit as well. Occlusion can also be used as a "dirt" pass to get those nooks and crannies dusty, dirty, etc.

I use ambient passes to add some ambient light to a render. Just think of it all as adding, subtracting, and playing with light through pixels.

04 April 2005, 02:48 AM

What is the easiest way to render out occlusion and ambient passes using maya 6.5?

Is both the passes single colour? recently I have seen a sample with texture and colour?

04 April 2005, 11:26 PM
Mental ray will render this. There is a "dirtmap" shader on the web somewhere, I don't have my links at work, but look for mental ray and dirtmap or ambient occlusion. But, Maya 6.5 has a dirtmap shader (or it might be a texture node) built in. Look for it in the mental ray tab when creating a shader or texture. Works great too. I'm on a project where we're using ambocc passes in the comp, but I don't know if the shaders are using the built in ambocc or using the dirtmap shader, I'm comping...

04 April 2005, 12:14 AM
I have a written a tutorial on exactly this sort of stuff, unfortunately it is written for shake. Although I regularly use after effects ! Have a look at this link :


the concept is exactly the same in after effects just the actaul process is slightly different. Have a lokk at these tuts and then if you want me to do a version in After Effects shoot me an email and I'll cobble something together !!!

05 May 2005, 10:32 AM
Personally, I would love to see an AE tutorial on this.

05 May 2005, 06:30 AM
I'll put a tutorial together as soon as I have some time, maybe in a couple weeks when I finish the current project I'm on. That is unless someone beats me to the punch.

05 May 2005, 09:49 AM

Ok thanks for the requests :)... I have redone the two tutorials from my website in AE I am just in the process of writing the Html documents so I can up load the whole lot. Will be there in the next day or two !


05 May 2005, 06:12 AM
Thank you so much for your time!:thumbsup:

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