[feature proposal] static AO recording

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ebrain
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[feature proposal] static AO recording

Post by ebrain » Sun Jul 18, 2004 9:39 am

Hi guys !

It could be cool if we could store AO render data in a file when it's static, no ? It's one of the feature of the new MAYA renderer (Turtle, isn't it). U know that AO is especially slow, and if the scene is static and that the artist wanna do an anim, I think it must speed up the rendering process...I don't think it will be hard to code, no ? (I'm not coder, so xcuse me if I'm wrong).

Please comment...give u'r mind about !
Cheers,

z3r0_d
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Post by z3r0_d » Sun Jul 18, 2004 10:07 am

baking a raytraced result into a texture?!

... yeah, not to be offensive or anything but blender has no similar capability now [so, not that coding it would be non-trivial, but it would be a lot of code] and I wouldn't expect this to come at a whim

IanCalvert
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Post by IanCalvert » Sun Jul 18, 2004 1:13 pm

Is the AO backwards traced? If so, moving the camera would present areas that had not been calculated.



Ian

ideasman
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Post by ideasman » Sun Jul 18, 2004 1:56 pm

it would be possible to take a similar approch to baking radiosity- bake AO into the vertex colours, then it would be stored.

The thing is that in a way its alredy possible to do this, just with radiosity not AO.

There are ways to put the radiosity into a uv image if needs be.

- Cam

IanCalvert
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Post by IanCalvert » Mon Jul 19, 2004 12:40 am

It couldnt be baked if it is backwards traced, and if it isnt, why not? That would provide a huge speed increase. Off topic here a bit, sorry.


Ian

kid_tripod
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Post by kid_tripod » Mon Jul 19, 2004 4:09 pm

I just got sent this as part of a Renderman promo thing:
http://www.techimage.co.uk/resources/pr ... ion_1.html

With the great quote: "Ambient occlusion pass. Using raytracing can effect render times significantly. An alternative method would be to use depth maps. In this case Ray tracing was used and the render performed in sections to ensure practical render times."

Great to see even with Maya/PRMan you still have fun there . . .

ebrain
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Post by ebrain » Tue Jul 20, 2004 1:01 pm

So, LOD and myself, we've spoken about the storage of AO data...'cause this is the topic :) The problem is, to store AO data in a file in order to re-use it when u want ! Why ? Here are some examples :

> AO data is only based on the scene geometry...not materials ! Think about it : when you have a big scene to render, the materials may not be as you want... No problem, since u have stored the AO data ! So you fix the materials, then you restart the rendering...but no AO work ! (since AO buffer is still the same !). It will really speed up rendering, I think...
> Even if you have a static scene with AO...and you wanna do an anim with ! You just have to process AO one time[/ b] ! :wink:

So, in some words : how can we store the AO Data Buffer in a file, and then, how could we re-use it simply... :roll:

matt_e
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Post by matt_e » Tue Jul 20, 2004 2:14 pm

ebrain wrote:> AO data is only based on the scene geometry...not materials ! Think about it : when you have a big scene to render, the materials may not be as you want... No problem, since u have stored the AO data ! So you fix the materials, then you restart the rendering...but no AO work ! (since AO buffer is still the same !).
Well, you can already do this extremely easily - just give all your object white materials, render the image with AO, and save the file. Then render and re-render your non-AO image as you wish. You can then open up an image editor or video editor and layer the AO image on top using a 'Multiply' blend mode.

ebrain
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Post by ebrain » Tue Jul 20, 2004 2:19 pm


Well, you can already do this extremely easily - just give all your object white materials, render the image with AO, and save the file. Then render and re-render your non-AO image as you wish. You can then open up an image editor or video editor and layer the AO image on top using a 'Multiply' blend mode.
Well, sure this method will not done the same results... :cry: Too aproximative as my own sense. Then, how can you do for anims ?

Cheers,

matt_e
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Post by matt_e » Tue Jul 20, 2004 2:21 pm

With a video editor. Not saying that more intelligent caching of render data would be useless, but there are workarounds available for now.

ebrain
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Post by ebrain » Tue Jul 20, 2004 2:27 pm

With a video editor. Not saying that more intelligent caching of render data would be useless, but there are workarounds available for now.
Yep, but that is not what I said... I said that the AO Data Buffer is still the same all anim long even if the scene is static ! So you have to process AO 'one time' (in only one frame so !) to do what I said...not to calculate AO all anim long !

Cheers,

matt_e
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Post by matt_e » Tue Jul 20, 2004 2:30 pm

ebrain wrote: Yep, but that is not what I said... I said that the AO Data Buffer is still the same all anim long even if the scene is static ! So you have to process AO 'one time' (in only one frame so !) to do what I said...not to calculate AO all anim long !
Ah, right. I was assuming you had moving objects, which would make the AO solution different each frame - my bad.

IanCalvert
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Post by IanCalvert » Tue Jul 20, 2004 9:48 pm

Does this mean that AO is not backwards traced? Thats means there is a lot of data that is being calculated but isnt being used (all of the backs of objects, for a start).


Ian

ebrain
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Post by ebrain » Tue Jul 20, 2004 10:03 pm

Does this mean that AO is not backwards traced? Thats means there is a lot of data that is being calculated but isnt being used (all of the backs of objects, for a start).
Yep, I think it could be a good start to optimize AO, no ? I've proposed to export AO solution for certain cases, but no backward process must speed up rendering a lot, and for all cases ! :shock:

Cheers,

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