Ok,
After reading Blair Burtains 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
What EIAS need to have a volumetric rendering?
MagicEgger
#1
Igors
#2
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
Igors
#4
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
#5
Thankssssss a lot the answer.
I hope Blair clould explain what means to him too!
Thanksssssss
Tomas Egger
harryb
#6
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
#7
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
That’s a question for EITG
Igors
#9
Harry, we learned this great plug-in in all details. Be sure, a role of host is only auxiliary there
NorthernLights
#10
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
#11
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
#12
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
Vizfizz
#16
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
#17
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
#18
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
#19
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.