AO pass within final render

[padre.ayuso]

I was wondering if there is a tutorial or a way to render your AO pass within the final render in itself. In the office we are pretty good at doing the AO Pass as its own and then compositing this in PS, but I wanted to know any method of doing the AO pass within the final render, if that makes sense. Any valuable data would be great!

[Camby1298]

Look to turning on AO within your A&D Shaders, that will burn the AO into your Renderings

[ivanjay]

Look to turning on AO within your A&D Shaders, that will burn the AO into your Renderings

 

What is the advantage to doing this? I never render separate passes for composition and am starting to get curious if i should be.... Does it increase render time?

[padre.ayuso]

What is the advantage to doing this? I never render separate passes for composition and am starting to get curious if i should be.... Does it increase render time?

 

The AO pass will give you depth, you should totally do this. I'm not sure about burning it into the image, as it takes away my control over it. I guess it is still better to do an AO pass and put it in PS then turn the layer to Multiply and in some cases reduce the opacity. That, all by itself, will give you any and shadows in the room. The rest of the passes, such as depth and so on, are worth checking into and we are here at the office, but I was hoping to find a way to do this so that I could put it in the image but not burn it into the image in 3DS Max. Perhaps Combustion will do the trick.

By the way, it does not increase the render time to do an AO pass by itself, maybe a total of 2 minutes for very complex scenes and depending on your AO Pass settings, but overall very simple to do.

[ivanjay]

So can we back up a bit here cause I am getting confused.

 

You do not recommend burning it in. How would I create it in a separate pass?

And if I do it in a separate pass you are saying in photoshop I can see it is as a diffierent layer and "turn it up or down"?

[padre.ayuso]

You do not recommend burning it in. How would I create it in a separate pass?

And if I do it in a separate pass you are saying in photoshop I can see it is as a diffierent layer and "turn it up or down"?

 

Well, yeah, if you can create a separate pass, why burning it in, cause after all, in PS you can take away what you don't like or bring down the opacity if it is too much... right? You create an AO pass... well, by creating an AO pass... Create the AO material and put it in the Material Override box in the Render Panel. Turn off your GI and your Exposure Control and you will have the AO pass... Those other programs mentioned above seem to do what I wanted, but I'd like that to be incorporated within MR or 3DS Max, so I don't have to open other programs. Hope this helps you.

[ivanjay]

Well, yeah, if you can create a separate pass, why burning it in, cause after all, in PS you can take away what you don't like or bring down the opacity if it is too much... right? You create an AO pass... well, by creating an AO pass... Create the AO material and put it in the Material Override box in the Render Panel. Turn off your GI and your Exposure Control and you will have the AO pass... Those other programs mentioned above seem to do what I wanted, but I'd like that to be incorporated within MR or 3DS Max, so I don't have to open other programs. Hope this helps you.

 

Silly question, how do I create a AO material in Max Design 2011?

[Tsukiyono]

So can we back up a bit here cause I am getting confused.

 

You do not recommend burning it in. How would I create it in a separate pass?

And if I do it in a separate pass you are saying in photoshop I can see it is as a diffierent layer and "turn it up or down"?

 

If I understand right...

 

If you render in separate passes, it will give you difference images for each pass. So AO pass, final render, Spec map etc. Then once its taking into photoshop, you load all of the images into their own separate layers ( I would think final render being the bottom layer). Then you change the blending options and the opacity to suit your needs.

 

I think your confusion might have stemmed from the conversation about it being all done in max. What he meant by that I believe was that if it was all done inside of max, there would be no use of photoshop at all, which in turn, he would be stuck with the one render, which would allow no customization at all to the AO pass in this case. Which is a big no no really, as the programs themselves very rarly ever give you perfect results.

[ivanjay]

If I understand right...

 

If you render in separate passes, it will give you difference images for each pass. So AO pass, final render, Spec map etc. Then once its taking into photoshop, you load all of the images into their own separate layers ( I would think final render being the bottom layer). Then you change the blending options and the opacity to suit your needs.

 

I think your confusion might have stemmed from the conversation about it being all done in max. What he meant by that I believe was that if it was all done inside of max, there would be no use of photoshop at all, which in turn, he would be stuck with the one render, which would allow no customization at all to the AO pass in this case. Which is a big no no really, as the programs themselves very rarly ever give you perfect results.

 

So why would you ever use effects if they are of no use for post production? Does composite allow you to play with those settings?

[Tsukiyono]

Silly question, how do I create a AO material in Max Design 2011?

 

Double post sorry,

 

Turn on mental ray in your renderer.

Then in your material window, click on the diffuse slot in the blinn basic parameters, select the ambiant occlusion map.

Then follow the steps above in Padres post. Fairly simple in all honesty. Although, I am not using max 2011, so I guess perhaps some of the steps might have changed?

[Tsukiyono]

So why would you ever use effects if they are of no use for post production? Does composite allow you to play with those settings?

 

Exactly. Compositing after the fact gives you full control over final look. Doing it all in max does not.

[ivanjay]

Easy enough, now another simple question.....

 

Why would you shut off Indirect lighting... Wouldn't you want that shadow information in the AO pass?

[padre.ayuso]

Easy enough, now another simple question.....

 

Why would you shut off Indirect lighting... Wouldn't you want that shadow information in the AO pass?

 

Give it a try, I usually get a bunch of error messages with Photons. With the FG, it also makes no difference. Give it a try every way, and it should all turn the same results. The only difference would be on your AO settings.

[Gary Ledgerwood]

This was the best tutorial I had seen on this topic. Helped me out greatly! http://3dsmaxrendering.blogspot.com/2008/04/ambient-occlusion-pass-for-interior.html

[Tron]

I know it's been a while since this thread's been active, but I was looking into accomplishing the same thing and could not figure out which method is best (because there are so many ways to generate an A/O pass). This is what I found:

 

if you go to render elements -> add mr shader element (might not be called exactly that, its near the bottom), set it as AO -> you can drag and drop that into your material editor and adjust the settings. it will give you a nice ao pass to composite at the end of the render.

 

Thank James I for the tip.

 

-Tron

Edited October 4, 2010 by Tron

[mdviz]

For those who are still confused on how to create a AO pass try this script. It converts you whole scene, renders the AO pass then converts it back. It is an invaluable free tool that many users have.

 

It also instantly creates object masks (including sub object selections), reflections and shadow passes, Extremely useful for fixing theose problems in post.

 

It can do each pass as a network render so you can submit and carry on working, however even the most complex scenes, 6mil+ polys only takes a few minutes to render an AO pass.

 

http://www.scriptspot.com/3ds-max/scripts/quick-passes

 

Remember to always back up work before running any scripts!

Edited November 1, 2010 by mdviz

[ivanjay]

For those who are still confused on how to create a AO pass try this script. It converts you whole scene, renders the AO pass then converts it back. It is an invaluable free tool that many users have.

 

It also instantly creates object masks (including sub object selections), reflections and shadow passes, Extremely useful for fixing theose problems in post.

 

It can do each pass as a network render so you can submit and carry on working, however even the most complex scenes, 6mil+ polys only takes a few minutes to render an AO pass.

 

http://www.scriptspot.com/3ds-max/scripts/quick-passes

 

Remember to always back up work before running any scripts!

 

Amazing that you put this together! I have not tried it but absolutely will be keeping this in my toolbox for the next one! I have 2011 so hopefully it will work, cant imagine why not...

[mdviz]

Amazing that you put this together...

 

I am afraid it is not my script I also have been blown away with the time saved by it for years.

Give the credit to the author:

http://www.ardakutlu.com.

[exxoo]

if you go to render elements -> add mr shader element (might not be called exactly that, its near the bottom), set it as AO -> you can drag and drop that into your material editor and adjust the settings. it will give you a nice ao pass to composite at the end of the render.

-Tron

 

This just renders a white image for me..

[TSuess]

Here is my Ambient Occluison Tutorial: http://www.renderededge.com/2011/01/what-is-ambient-occlusion.html

 

Thoughts/critiques welcome.

[mdviz]

Thoughts/critiques welcome.

 

As an 'end user' the complexities of the algorithm you show is interesting to see though as an artist I must say that I wish to stay away from those heavy calcs and be more productive by just 'dumbly' using the software. Especially when there have been scripts created such as I have linked to previously.

 

Your tutorial shows how to apply the shader and how to use the Material Override within Max which is useful.

 

From an artistic point of view, your tutorial could show some detail of the effects of tweakin the settings of the Ambient/Reflective Occlusion shader with examples.

 

Starting say, with the 'Samples' setting which by default is very low. Then 'Spread' and 'Max Distance'. These are settings that are tweaked most often. An explanation of these settings with examples might be more useful.

 

One of the problems with AO is that it is not always right for all objects in the scene 'artistically'. Your finished pic shows a single pass of AO where the walls might look OK but the joins in the floor boards seem too dark. A different AO pass might be required for some objects to fix this.

 

You could explain how to render different AO passes with different settings and along with the use of masks in Photoshop and applying different transparancey levels to get the artistic look that might be required.

 

The same techniques can also be applied to animation using After Effects.