Ambient Occlusion in 2D, free shake plugin!

DavidW · **Ambient Occlusion in 2D, free shake plugin! -** November 5th, 2008, 10:32 AM

I've developed a Screen Space Ambient Occlusion plugin for Shake that I'm releasing for free (as all of my other plugins). It's using only a depth pass to calculate a kind of ambient occlusion pass. First it's calculating a normals pass from the depth pass that is later used for the occlusion sampling. If you got a normals pass already you can feed that into the node as well to get a better result.

The whole plugin is actually a macro that includes 3 compiled plugins:
depth -> normals
depth&normals -> noisy SSAO
noisy SSAO -> smooth SSAO
These ones doesn't show up in the interface as default, but you still have them there to use as you want for other stuff. I can see uses for generating a normals pass from a depth pass, but also being able to blur stuff without blurring the edges of objects or sharp features.

The plugins are downloadable here:
http://www.pixelmania.se/shake

I have optimized it as much as I can for now and it's still slow, sorry about that. It's just loads that needs to be calculated for each pixel.

Hope you like it!
Cheers, David

gottony · November 5th, 2008, 12:10 PM

Thanks David!

gboom · November 6th, 2008, 02:38 AM

Wicked David, looks cool.

Richard.S · November 6th, 2008, 04:38 AM

That's really impressive David, I'm definitely going to try it out when I get home. Sometimes when I see plugins like this I wish I still was working with Shake during the day, but don't tell Theo okey?

mrrafs · 07:11 AM

wow!!! -good set of plugs.. there a whole load of stuff id like to learn here.

yeah that 3d-keyer in S.Wights book throws alot of people because of the typo (i've got 1st ed.) in the expression) . I find it works great in HLS with a little channel selective rank filtering. So how did you turn it into a magic wand with edge detection? http://en.wikipedia.org/wiki/Flood_fill
what implementation did you find works? can it be done with macros?
sorry for all the question just really excited at all this cool stuff.....

DavidW · November 6th, 2008, 08:06 AM

Glad you guys like the idea!

mrrafs: The WandKeyer is using a 4-way stack based FloodFill to isolate the single continuous area that needs to be extracted. I don't think it's possible to create with a macro... that's one of the big reasons I did it as a plugin.

mrrafs · 10:14 AM

thanks.. i think i know how to do it in a macro
- i'll use x3186688(2k) stat and crop nodes

Back on topic.
Why do all the 2.5d lighting tools use a depth aov instead of position(Cam) & normal(Cam)?
Is it because some 3d packages are not able to render normals cheaply, anyone?
ta

DavidW · November 6th, 2008, 10:14 AM

Hahaha, true!

Hugh · November 6th, 2008, 10:45 AM

Most 2d relighting tools *do* use normal and position data. David's plugin is quite cool because it can give normals from a depth pass.

I think that a lot of people just use depth because they know how to render it - as it's useful for things other than just relighting (fog, and stuff like that) - a lot of people seem to have trouble figuring out how to get normals and position data out of their renderer.

ericohman · November 10th, 2008, 05:43 AM

impressive plugin!

2d relighting, how do you do that using the normal map? never worked with normal passes? do you re-order to get the desired lightangle then expand/compress etc or how is the normal pass being used in Shake?

DavidW · November 10th, 2008, 08:14 AM

Thanks!

Shake haven't got any built in normal based relighting tools. You either have to write your own or try some free macros out there. Check this one out for instance: http://www.fxshare.com/shake/downloa...ht3D-3810.html
Do pick it apart to learn what it is doing. You'll need some basic 3D math knowledge of linear algebra and such (dot products, cross producs etc.). Happy learning!