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MagicEgger
03-12-2006, 05:02 PM
Ok,

After reading Blair Burtain’s interview I started to ask myself “What EIAS need to have a volumetric rendering?”.
So, my developers friends, help me to understand this issue.

Thanksssssssss


Tomas Egger
;)

Igors
03-12-2006, 08:48 PM
Ok,
After reading Blair Burtain’s interview I started to ask myself “What EIAS need to have a volumetric rendering?”.
So, my developers friends, help me to understand this issue.
Tomas Egger;)
Our advanced user friend, we could ask you: what is a volumetric rendering? :) But Ok, let us try to answer what we know

"Volumetric rendering" is a very blurred/undefined term/definition imho, each one uses it as he wants. In any case it's a "rendering something not polygons/geometry". It can be a rendering of fog, smoke, clouds etc. Ofren "volumetruc rendering" is related with hair/fur or even with grass cause it's clear long ago: they cannot be rendered well with phong shading + megatons of polygons.

We know nothing about 3d apps that implements volumetric rendering directly. Instead hosts(LW or Max for example) support a special class of plug-ins to create volumetric effects. So, "volumetric rendering" is just an advanced plug-ins/shaders API. The host's support is pretty simple: a plug-in receives a segment of ray(input) and returns to host a some color and transparency (output). The host automatically adds this output to final render. For all other things (for example, where a cloud should be located etc.) the plug-in is responsible itself.

So, don't have illusions that "volumetric support" is a huge improvement, it's a support only

Vizfizz
03-12-2006, 09:49 PM
Would Northern Lights Psyclone be the closest thing we have to a volumetric equivalent?

Igors
03-12-2006, 10:29 PM
Would Northern Lights Psyclone be the closest thing we have to a volumetric equivalent?Hi, Brian
We know nothing about Psyclone, that's a question for Blair. Just there is no "more volumetric" or "less volumetric", a result's quality/usability depends from plug-in itself, not from host's support. If, for example, a volumetruc plug-in creates a cloud of smoke, then absolute same calculations are performed in EI, LW and Max (and finally you see same result image anywhere).

However, host's service makes many things easier for developers and users. For example, if we render something volumetric in Max, it's enough to be "atmospheric" plug-in, and Max takes care about all others. We can do same in EI shader, but we must burden user with some "considerations/agreements", sorta "please create a sphere surrounds your scene, EI shaders works with surface only". There is also a series of problems if another one object is inside volumetric cloud - in fact EI plug-in/shader should provide "atmospheric service" itself.

Nevertheless, any host's service doesn't make plug-in's result better or worse - it depends from plug-in only

MagicEgger
03-13-2006, 04:31 PM
Thankssssss a lot the answer.
I hope Blair clould explain what means to him too!

Thanksssssss

Tomas Egger

harryb
03-13-2006, 05:48 PM
I'm certainly no programer, but isn't volumetric rendering created by using ray marching algorithms? Isn't that the way EI calculates subsurface scattering?

Just curious.

Igors
03-13-2006, 06:23 PM
I'm certainly no programer, but isn't volumetric rendering created by using ray marching algorithms?Yes, ray marching technique is used always AFAIK. But inside plug-ins, not in hosts. It's an accumulating alpha/color along ray's segment (same as EI Smoker does). And ray marching is one of most easy and pleasant things on the way to create a good volumetric effect :)

Isn't that the way EI calculates subsurface scattering? Just curious.
That's a question for EITG :)

harryb
03-13-2006, 06:30 PM
Thanks Igors! Do you think this is how Hypervoxels are interpreted in Lightwave?

Igors
03-13-2006, 07:26 PM
Thanks Igors! Do you think this is how Hypervoxels are interpreted in Lightwave?Harry, we learned this great plug-in in all details. Be sure, a role of host is only auxiliary there :)

NorthernLights
03-14-2006, 02:42 AM
Psyclone is a volumetric effect that does ray-marching internally but it has limitations. First, some sort of geometry must be present in order for the shader to be called by Camera. Psyclone builds a cube on which to do the rendering but you're not aware that it's there. The resulting image is sort of projected onto the faces of this cube.

The second problem is that it doesn't cast really accurate shadows because image is really being projected onto the faces of the cube. For example, if you turned on light rays and tried to shine the light from the top of the cloud pointing down and viewed the scene from the side, you'd see the rays begin from some invisible bounding box.

Psyclone also doesn't respond to lights that exist inside the volume. It's really meant to do clouds which are usually only illuminated by the sun which is very far away.

Technically, a lot of shaders exist in 3D space e.g. anything that uses Perlin Noise. If there were a way of creating volumes that are ray-marched and the ray-marcher called a shader, neat things would be possible.

Igors
03-14-2006, 12:31 PM
Technically, a lot of shaders exist in 3D space e.g. anything that uses Perlin Noise. If there were a way of creating volumes that are ray-marched and the ray-marcher called a shader, neat things would be possible.
We don't share the opinion about neat things possibility.

What rational volumes the host should provide? Gizmo shapes like in Max (simple primitives - sphere, cube, cylinder etc.)? Not a big help for developer. Note also that analyze inside/outside gizmo is a work for max plug-in, not for max host. Custom shapes (any polygon object)? Can be implemented with EI shader (though, yes, need to call RT to detect volume)

Second, Perlin noise and Volumetric are not good friends, sure. It becomes obvious if Perlin noise is used as a layer of clouds (as a shape - in c4d etc). The range of interesting volumetruc effects is very narrow, we've no illusions that ray-marching + shader would give even something approximately usable. Also straightforward ray-marching produces very poor and sharp self-shadows

MagicEgger
03-14-2006, 02:27 PM
Hi,

What we need to have a plug-in like Shave and Hair cut?
Because its really dificult to have millions of hairs using geometry.
www.joealter.com

Thankkkkkkksss

Tomas Egger

Igors
03-14-2006, 03:18 PM
What we need to have a plug-in like Shave and Hair cut?$, Tomas, $

Vizfizz
03-14-2006, 03:58 PM
How much money?

Igors
03-14-2006, 04:17 PM
How much money?
Sorry, can't answer - that question is not for public discussion

Vizfizz
03-14-2006, 04:22 PM
Well Joe's Shave, I'm assuming, has a cost right? You have to license the technology. That's what I was wondering Igors.. Not your specific EIAS developers cost. Though I would be intrigued to know what that is...

privately.

Don't get any ideas folks... I'm probably not that rich. lol

FelixCat
03-14-2006, 04:24 PM
How much? :drool: I remember Brian was in conversations with Joe Alter about licensing his technology... i suposse was too much for the posible EiAS market and nothing happened :banghead:

FelixCat

Reuben5150
03-14-2006, 04:44 PM
Could we not build somthing like shave from "scratch" ?, or add to-improve existing tools ?, FiberForge ?

And if shave costs $399 then thats what i'd expect to pay for simlar tools/results.


Reuben

Igors
03-14-2006, 05:14 PM
Could we not build somthing like shave from "scratch" ?, or add to-improve existing tools ?, FiberForge ?

And if shave costs $399 then thats what i'd expect to pay for simlar tools/results.

IMHO EIAS has a lot of what normally should be in plug-ins/shaders (examples: blurred reflections, normal maps, all material's edge settings, morph, skins etc). But not hair/fur - that should be in host.

Vizfizz
03-14-2006, 05:44 PM
Given the intensity of such calculations.. yah.. you're probably right.

harryb
03-14-2006, 06:14 PM
Again, I'm certainly no programer, but if someone's working on a cloth plugin for EIAS, isn't that just about as difficult as creating fur and hair? I mean Placer Deposit looks pretty good to me. Would a soft body simulator for EIAS make it possible to do hair too? -- Kind of like taking what Placer Deposit does and making it flow?

Am I being naive here?

Thanks!

threedeworks
03-14-2006, 07:53 PM
speaking of volumetric effects, one of the most useful additions to EIAS would be also some kind of volumetric instancing like this:

http://www.happy-digital.com/instance.asp

have a look at the samples.

this kind of plugin is very interesting because 'natural looking' scene elements (like grass, fur, pebbles, trees, rocks, clouds, ehm ...even teapots!) could be rendered in enormous quantities without actually handling geometry. rendertime increase for scenes with millions of instances should be much less dramatic than with real geometry instancing.

i did and i'm actually doing some projects with landscaping elements like flowers, grass and trees. in such scenes, even with camera a limit when operating with real geometry is fast reached.

is there any hope? in theory, with the current SDK, is such a plugin possible? with shadows, transparencies and reflections?

cheers

markus

Igors
03-14-2006, 07:54 PM
Again, I'm certainly no programer, but if someone's working on a cloth plugin for EIAS, isn't that just about as difficult as creating fur and hair? I mean Placer Deposit looks pretty good to me. Would a soft body simulator for EIAS make it possible to do hair too? -- Kind of like taking what Placer Deposit does and making it flow?

Am I being naive here?

Well, maybe not naive, but too optimistic, really :)

Igors
03-14-2006, 08:31 PM
is there any hope? in theory, with the current SDK, is such a plugin possible? with shadows, transparencies and reflections?
No, Markus, we see no ability to implement such EI plug-in

threedeworks
03-14-2006, 08:51 PM
No, Markus, we see no ability to implement such EI plug-in

ok, thanks for dropping me back into reality :)

DickM
03-15-2006, 02:00 PM
why can't that kind of plugin be implemented? Problems with EI as a host? API limits? Could it be implemented if it wasn't a plug but part of EIAS?

Thanks

DickM
03-15-2006, 02:01 PM
Markus isn't the only dreamer here! :rolleyes:

Igors
03-15-2006, 03:03 PM
why can't that kind of plugin be implemented? Problems with EI as a host? API limits? Could it be implemented if it wasn't a plug but part of EIAS?

Thanks

Markus isn't the only dreamer here! :rolleyes:

Yes, here is the place where EI shader/plug is helpless without host's support. We've experimented on this way several years ago. The attachments are our virtual grass attempts (hmm.. looks naive a bit :rolleyes:). The render time is quite acceptable (no RT though), but instead we've had 2 serious problems that we could not solved.

1. Yes, without polygons we can fill unlimited areas with a grass. But we've lost a lot together with polygon/geometry limitations. And the material is the first and most painful. The shader should do all (absolute all) itself: color, texture, specular, bump etc. - no any side help cause all is linked to polygons we've not. There is no way in to force Camera to render a polygon "on fly" - the polygon should be passed to render engine and saved.

2. Also very unpleasant: AA (maybe same problem is also in plug-in that Markus posted a link). As you know, Camera shades edges very carefully - a several "sub-pixels" are mixed together to obtain a smooth result. But with our "virtual geometry" the render cannot detect where more or less sub-pixels required. So, jaggy grass edges :sad:

And, hmm... when we see a next such cool thing (as this LW plug-in), we usually do following: first we try to forget about it. Then (next day) we open demos/samples again and see them (and their render quality) whith calm emotions. It's veeery helpful ;)

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