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GI in VOPs?


stu

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random thoughts:

-bevels and checkers are cool....proceeding to shamelessly ripoff the idea :)

-weird how we get a shadow VOP but no diffuse or spec VOP... oh well thank god for inline

-the sharp shadow should erode within the radiant shader pass...but then it prevents correct spill light to be calculated....

-hey stu, did you blur any of the passes before compositing them?

cheers...

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Nope - no blurring. Right outta the box.

stu

hmm....actually...you're doing involuntary blurring....simply assigning a texture map to your objects (assuming you're using the default anti-aliased VEX shaders supplied by SESI) you're filtering your textures....besides reintroducing grainy textures in a renderer has the side effect (no pun intended) of blurring them...it's a degradation...but one that serves our purpose, since -to quote Jason - "all that GI stuff is pretty blurry anyways" ;)

the reason why I asked was because I'm working on a version that'll let you make the whole composite within one shader, one render pass....

and the preliminary results I got so far still had the graininess of the first pass....and the only thing you're doing different is reassigning te texmaps onto the geometry for you third pass.....

anyways............your pictures ROCK, man....

any chance you could make a quick interior, just for kicks?

cheers!

PS: you guys might like this:

http://www.pegtop.net/delphi/blendmodes/

kinda useful....

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Hi sirogi,

Yeah, it had occurred to me that by having the geometry reflect another set of geometry that was texture mapped with a previous render that I might he (involuntarily) scattering the rays even further. It's interesting to note, however, that the texture mapped geometry never actually gets rendered, but is only reflected by the real thing.

I can't wait to see what you're cooking up over there - I'd love to see a working version that eliminates the need for these multiple passes!

I'll try to knock off a quick interior today or tommorow...maybe a typical sun through the window sort of thing...

Cool link - colour can be a complicated thing (who ever heard of a subjective vector, anyway?:P).

stu

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I can't wait to see what you're cooking up over there - I'd love to see a working version that eliminates the need for these multiple passes!

he he he he...guess I talk too much... :) I'm still working on the shader so that in absence of environmrent objects (dome, etc...) it would still give you some spill atop the regular render....

bad thing is, as soon as you turn on any kind of shadows, the whole thing bombs, and starts giving you black pixels all over the buckets....the good new is: you could output render passes (I"ll have to set that up) and do very straightforward compositing to get the cast shadows back in...

here's a sampler of the working (with environment) render...

PS: the subjective vector? the one pointing at me right now?

:P

post-9-1035702264.jpg

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aaand...for that simple interior...

I noticed that the system gets pretty weak pretty quick...looks like it's taking only one bounce into account... which is fine for the shperes and cubes but doesn't quite cut it when confronted to the "real world" ;)

it would help reflect the result of the first bounce into the second one...just to mellow things down...

oh well...more headaches...still look s good as is...

cheers!

post-9-1035702478.jpg

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Very cool, sirogi. That "simple" interior looks pretty complicated, if you ask me! :lol:

We never learn, do we? Tests always work on a single sphere at 0,0,0. Then suddenly when we apply research to something that actually has to work - BOOM! It blows up. Maybe SESI should provde a "simple interior" as one of it's primitve types. :blink:

It actually almost looks like the points in the model just need to be made "unique" with a facet SOP and the corners are being rendered smooth, even the ones up to and above 90 degrees.

I should be able to post my interior this evening.

This is actually very encouraging - it's nice to see that I'm not the only one pushing for a GI VEX solution. We're a lot farther that we were a week ago. Thanks to everyone for the comments - I'm sure that we'll walk away from this with a viable solution ( I just wanna make cool pictures!). I'm just sick of seeing these amazing renders come from every other piece of software leaving us in the "no bounce light" cold.

More to come!

stu

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have you ever tried to combine this shader with textures also ? because

normally you need different kind of textures for every obj ( not only phong and lambert materials ).

If I start to applay textures the hole "effect" is gone :angry:

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mike: the regular pic took well..I'll need help redaing the houdini stats....it returns something like (xxx u. xxx s.)

as soon as I understand that I can get back to you ;)

the rough estimate is 5~7 minutes fot he ball, cube thing...

for the interior, I cheatd and used multiple machines (~7) and went 1440*972, 256 shader samples, 5 AA samples..(really wanted to crash that thing...) and it returned after 20 min....which in my book is pretty cool! :)

btw...the last posted version was bogus, I used refelection masking inside the shader, so for it to err.."work" you'd have to prefix any environment light-casting object by "env"...pretty simple for a requirement..

just attached the "more accurate version"...

stu:

I had the interior beforehand...asking for one was a trick question ;)

and the model is faceted...just comes up smooth..if you had the hires version, looking close, you'd see the edges...

the more I work with this shader, the more I find shortcomings...of course, looks "interesting", but to get the extra "oomph" some more hacking around is required....if you look closely at the previously posted images for indirect lighting, you'd notice that all we're getting is first level bounce: green cube casts green spill and gets white bounce...but the frist-level bounces should mirror each-other again, and average to a pale green!

.....that's why it's sensitive to color (like mike pointed out)...because the energy is not getting carried past that first bounce...ideally, the second bounce would "see" the result of the first bounce and carry it deeper into the scene but that implies yet a second loop, and you won't have to brighten the colors as much....I noticed that whenever I used materials whose average brihtness go below .5, it all goes dark...you barely get light sipping through...I had to extensively cheat to get the picture you're seeing by using very bright colored materials....not the ones that would be definitve...

anyways, it's not practical to be used in animated backgrounds, because of the noise introduced, so, like Jason said, baking the illumination into the textures or making static images to be composited on top of others seems the way to go....incidentially, all the shader design was made in shake, outputting the vasious stages of the shader....I kinda like that better, since you can really fine-tune your passes in post...

PS: cast shadows are still not in the equation....I believe they would add a lot to the thing...too bad its buggy...

aaargh....so much to do , this thing is eating all my time, haven't gotten any "real" work done, so guess I'll just post a hipfile soon and go to sleep on that...

end of rant! CHeers!

post-9-1035752548.jpg

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