# F0001- How to composit render passes in Adobe After Effects ? #

This tutorial is the Adobe After Effects version of the Composting render passes in Fusion. Here we will discuss about composting 3d passes inside of Adobe After Effects. You can download the footage from Digital Fusion version. In this page only After Effects project file will be available for download.

#Final Output (FLV File, Hover mouse to Get Playback controls)


Create a folder CGPasses and copy the footage folder from the eyeon fusion version copy the footage folder inside the CGPasses folder you just created. Also extract CGPasses.aep from this page inside the same folder. Once you that launch after effects and open the .aep project. This is a completed project. Click on the new comp icon and create a new composition. Set width/height to 640x360 and square pixles.

01. First drop the floor diffuse and above it cube diffuse pass. Opacity 100% and Mode Normal. General rule for, "Order of the passes in composition" is that you start with the dark images towards the light images.

02. Drag in the Ambient Pass and set the Opacity to 32%. For Mode you can play with Screen but when I switched to Classic Color Dodge it gave me better results. It is up to your taste.

03. Now go for shadows pass. Drop it in. Set opacity to according the darkness of shadows you need. I have set it to 55%. You can always blur the shadows if you need to.

diffuse pass
ambient pass
shadow pass

04. Norma pass is a special pass. Normal pass is very vital when you want to interactively change the lighting or mood of your scene. We will use a special technique to achieve this result. Highlights are best seen in a black and white image. We use couple of effect here like BC, Hue/Sat and Channel Mixer.

First drop the normal pass in the comp window and set mode to multiply. Add Channel Mixer effect from the Effect menu and just change one setting, Click on Monochrome checkbox. This will change the image into black and white. Once you do that you can see the highlights clearly, next step is to add a BC effect to enhance those highlights. Add a BC effect and set brightness to 42. Now change the highlights interactively add a Hue/Sat effect above the Channel Mixer effect and rotate the Master Hue wheel, voila that is what we were looking for. Set the wheel according to the direction of highlights that suits you. One more effect we would add and we are done with this step. Add another Hue/Sat effect at the bottom of the effect stack and using the Master Hue wheel set the color of the highlights.

normal pass
channel mixer effect
normal passbrightness contrast effect
hue saturation

normal passnormal pass
05. Drop in occlusion pass. This pass is also known as dirt pass. When you add this it gives you nice contact shadows. Though it gives fantastic results but it is very expensive pass and take loads of time to render. Set mode to Multiply and opacity to 85%. Now add floor reflection pass and set mode to screen. You can always enhance the reflection and secularity effects by adding a BC node. Next add cube reflection pass. This pass is about the reflection of the cubes on the floor. Set mode to Screen or Add. I am happy with Add.

occlusion pass

06. Once you add the cubes reflection you would notice that some highlights are overlapping. This is the place where compositors use geometry matte (Masks) or cut matte as some artist call them. Drop in white matte floor pass and in cube reflection pass set track matte to Alpha Matte. This process will eat the overlapping mess.

passesgeometry mask
reflection pass
07. Next add specular pass and set mode to Add. Finally add luminance depth pass to give comp gradient fall of light from white to black pixels. Luminance depth pass is also used in Deep Pixel Category effects like fog3d, depth blur 3d etc. That we will cover in a separate tutorial. Set mode to Multiply and opacity to 60% of luminance depth pass.
passes passesluminance depth
08. Now we will give glow to the white lines of the floor. For this duplicate the floor diffuse layer and place it at the top. Add a color key effect to kill the orange color so that we can have the white lines only. Use the settings as shown in the image below. As you can see white lines are at the top of the cubes. What we will do now? Correct !! we will use geometry mask to eliminate that. Duplicate the white_matte floor diffuse layer and place it at the top. Change the track matte of glow layer to Alpha Matte floor_diffuse.
color key effect glow effect

09. Now we have come to end of this tutorial. I hope you would have liked it. If you face any problem during the practice of this tutorial feel free to ask at the forums. More tutorials on Fusion, After Effects and Maya are coming soon. Bookmark this site if you liked it.

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