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Guest Ivan DeWolf

"radiosity" shader

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very cool, much like a maya plugin that has been circulating around..

I was not able to get rid of the graininess by upping the sample number though...was wondering if anyone had any luck with this...

I was adding this with some other shader stuff in VOPs and was trying to

figure out a way to "soften" or "blur" the graininess.. anybody have any

suggestions to point me in the right direction?

thanks

david

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there might be something interesting one could do with unwrapping (mantra -u ..) these results and filtering them.

in the meantime, this would make a lovely VOP. anyone willing to take a few minutes and convert it up and post me an .optype for the codex? :lol:

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A Cornell Box render using the Radiant shader with only an Ambient Light.

Not the best Cornell Box render you'll ever see though. ;)

radiant_cornell.jpg

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Nice one, Steven..

Is it a high bias value thats causing the light spot underneath the sphere?

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Hey Jason,

I used a bias of 0.0005 & 1024 samples. It sure took a while to render. ;)

I can't tell you for sure what's causing the light spot. It could be the Ambient Light value or the Sphere.

I should probably remove the sphere from the floor's Reflection mask.

Cheers!

steven

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this would make a lovely VOP. anyone willing to take a few minutes and convert it up and post me an .optype for the codex?

I started to convert it. But it will be a week, not a few minutes. ;)

The black magic of shader coding.. :ph34r: ..Here I come.

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Good luck!

Well, you could "cheat" and compile it using "vcc -p" to produce a single radiance VOP which could be used easily with any VOP net. Or you could attempt to re-create the entire chunk of code into a subnet of VOPs too - which is I'm sure what you're talking about. It's a fantasic project to cut your VOPs teeth on, actually because it has if-then's and for-next loops and so on and it's not too big.

I'd also recommend comparing side-by-side renders of the VOP version to the .vfl version to verify your coding..

It'd be interesting to see if there is any speed difference.. I suspect not, actually.

B)

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Thanks Jason :lol:

I think I'm on the right track, with your help.

--

Tips for vop beginner like me

1. Function like getraylevel() is documented on...

houdini/houdini/vex/html/shading.html

2. Compiler option like -p is not documented (I'm afraid). You have to...

vcc -h

..to see the option.

3. If you want to build a single vop from radiant.vfl,

Compile with -p option, and put that .ds to folder..

houdini/houdini/vop/surface

And register the vop name on,

houdini/houdini/vop/VOPsurface

Good luck to me and u.

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Conversion time was faster than I thought. :P

Here is the vop, inside original hip which can be downloaded from odforce/download/

radiant.hip

48k bytes

--

I had no idea how to convert,

ambient() + .5*diffuse(nn);

So I had to use inlineVOP.

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Hi, Chang..

cool implementation, guess I have to admit you I got and hacked your file :)

hope you don't mind!

it got simplified quite a bit, using a lot of shortcuts (used the "lighting model" node to do the amb()+.5diff())

and I made a new version that adds more control to the original implementation...."tries" :) to take into account the lightsources (noticed all your lights were masked off)

made it in 10 min, so it's not all pretty....more like cooking, going on instinct...

still a lot more to enhance...write a responsive shadow shader that works with the scattered light instead of just multiplying it.....have more rays iterations that buildup the spill color, assign cusom wieghts to rays and make them do..er..stuff.....etc....

cheers!

PS: I had fun rendering the scene twice, switching the contribution to extremes, and compositing in photoshop!

PPS: I wonder how well would this model fare with texturemaps!

PPPS: as a personal preference I like to set ambient to 0 in shaders and never use ambient light.....experimenting with this shader, I'd take ambient OUT altogeteher....seems to give better results, since the shader handles the bounce light anyways!....

PPPS:rossy guys, can't post it yet...don't see the field where to post files

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it got simplified quite a bit, using a lot of shortcuts (used the "lighting model" node to do the amb()+.5diff())

.

.

PPPS:rossy guys, can't post it yet...don't see the field where to post files

Yes,yes! I've smelled something around LIGHTINGMODEL ! <_<

.

.

And I agree. Odforum need some kind of file-upload capability.

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wish I could show you all the shortucuts you can take while adapting this shader.......

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I have posted Sirogi's VOPnet in the VEX forum.

(btw, I have enabled attachments for this forum now.. please zip stuff if you can, before attaching it)

Cheers Sirogi/Chang/anonymous....

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