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Ultimatum
08-24-2005, 12:36 PM
Is there any ways to get the effect such as SgAmbOccs shader for FPrime1.5?
Like adding dirt to corners and so on.

I know that shaders donīt work with FPrime but is there any other way to accomplish the same effect easily?

I remember Gerardo introduced a way to use gradients and distances to nulls, but there setting takes forever, right?


- Ultimatum

Panikos
08-24-2005, 01:30 PM
Sure !

Use White Backdrop and render using FPrime Backdrop Radiosity.
You may need to duplicate your geometry with a WHITE COLOR version, erase all channels except the Diffuse.

Erase all lights, keep one at zero.
Disable Shadows, Reflections,Refractions.

mav3rick
08-24-2005, 05:06 PM
panikos
i was wondering.... if lw9 nodal shader works with fprime... there is few possybilities how he did it:
1.Newtek team opened lw9 SDK for worley support shaders
2.Nodal as shader will not work until it become part of core.
3.Worley gave newtek dev. team FPRIME sdk to implement it in NODAL (akka. g2 connection)

if 3rd is true i hope worley release public sdk for other shader developers to implement it!

Panikos
08-24-2005, 06:21 PM
FPrime doesnt have SDK.
SDK is like a TV-Remote Control, so FPrime cannot controlled remotely.

What is necessary here, is that a Shader collects all/some Surface parameters, process them and the result is still accesible by other shaders and LW all the time.
In other words, LW and plugins need to share common information.
Not read only, not write only, but Read/Write Always.

I cannot make assumptions about LW9 cause I havent seen it yet and often marketing words are very promising and far away from the real meaning.

So, lets see ...

Ultimatum
08-24-2005, 07:02 PM
Thanks, Panikos!

That method worked quite nicely. But that canīt be used for tightly located dark areas in corners etc.


- u

Panikos
08-25-2005, 04:11 AM
Yes, you can add some ambient to the scene or you can add some extra lum to the related object even though it will make the shading more grey than black.
Personaly I dont mind about dark areas, inaccessible to light. Makes it more natural.

:)

gerardo
08-25-2005, 05:39 AM
Is there any ways to get the effect such as SgAmbOccs shader for FPrime1.5?
Like adding dirt to corners and so on.


I think Panikos method is the way to go. You may use FPrime's BackdropRadiosity at least in two ways: composing this AO pass in post (using multiplied blending_mode with your "bounce_lights" passes), or using it as AO map (Front_Projection); in this last case you would need to define the camera motion first. These methods are useful if you have to render few frames or if the AO pass renders pretty fast (remember we can use denoise filters or tools like NeatImage for this pass)



I know that shaders donīt work with FPrime but is there any other way to accomplish the same effect easily?


Another way is bake BackdropRadiosity in textures as AO maps, using native LW renderer; then apply it in surfaces and render the final images in FPrime. This may be useful if the baking process is more faster than to render every AO frame in FPrime (supposing are many frames).



I remember Gerardo introduced a way to use gradients and distances to nulls, but there setting takes forever, right?


- Ultimatum


I guess you are referring to this technique (http://www.cgtalk.com/showthread.php?t=176195). In fact is pretty fast (even more than FPrime). As example, these images:

http://www.geocities.com/cgtalklinks/livingrooms.txt

takes about 7-9 minutes at video resolution and about 9-14 min at 800x600; the same scene in FPrime takes about 4 hours (MonteCarlo Radiosity), 7 hours with LW Interpolated Radiosity and 20 hours with LW MonteCarlo Radiosity. Setting the second image took about 3 hours (model optimization, texturing, surfacing and lighting; consider was the second time that I tried this technique in a complete room). However in this technique, gradients has been used to accomplish the radiance and scattering effect, the occlusion effect was achieved with SG_AmbOcc (by the brilliant Skidbladnir).



That method worked quite nicely. But that canīt be used for tightly located dark areas in corners etc.


Some ways to get dark areas in corners is using negative lights or subtractive gradients. I also listened that Otacon uses Value (procedural texture with falloff) to do the same thing :)



Gerardo

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