Volumetric render tests (large pics)

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Zybrand
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Re: Volumetric render tests (large pics)

Post by Zybrand » 19 Jan 2012, 20:36

Thanks for the advice Mathaeus it is much appreciated! to be honest my flow setups still need some work as well. We have Slipstream (simulator) and Fury for the project and they work really, sadly no emFluids but I am a fan. We are still in R&D for the effects work so I though I'd give the particle volume shader a go as well.

ha, Tekano we are after the same things, I am finding it quite hard to create. I had a look at your videos and your getting some promising results with the pyroclastic primitive aproach. I am looking through the Volumetric Methods In Visual Effects papers but most of the math there is above my head as well. In your first video Cube Powah v1 you mention that each particles color and transparency affected by the power lookup. What power lookup are you refering to and is this all you are animation or do the particles have movement as well?

My first attempts where large scale aproaches to I whole cloud system which I have gotten nice stills from in the past, but the problem is obvious with that. I just got un natural looking results that move like turbulance and not clouds.

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Tekano
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Re: Volumetric render tests (large pics)

Post by Tekano » 19 Jan 2012, 22:53

Zybrand wrote: ha, Tekano we are after the same things, I am finding it quite hard to create. I had a look at your videos and your getting some promising results with the pyroclastic primitive aproach. I am looking through the Volumetric Methods In Visual Effects papers but most of the math there is above my head as well. In your first video Cube Powah v1 you mention that each particles color and transparency affected by the power lookup. What power lookup are you refering to and is this all you are animation or do the particles have movement as well?
yeah I saw on the houdini forum that the most effective billowing example used this 'power lookup' its simply a mathematical operation called Exponentiation that uses 2 numbers one as a 'base' and another as the 'exponent' in XSI the node is just called 'Exponent' that bit is simple and I get, but the implementation into color & transparency , that credit definately has to go to BenP for his blog post here and here is a compound example for 2D lookup explaining all about it.

So I think Ive got the Power lookup working, its just the implementation of this with the pyroclastic noise is not looking so easy.
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Zybrand
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Re: Volumetric render tests (large pics)

Post by Zybrand » 20 Jan 2012, 12:15

Yeah the power lookup you have got going on seems to work well.

The blog links for blog.ioxu.com don't seem to work (The connection has timed out, The server at blog.ioxu.com is taking too long to respond.) :( but the wiki one works fine thanks :) .
I can only work on it again on monday but I will post so videos if I get anything interesting going.

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Tekano
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Re: Volumetric render tests (large pics)

Post by Tekano » 20 Jan 2012, 12:27

oh. BenP's blog works here from UK fine! was going to try and make the billowing stuff work as I wanted on a sphere first before trying with more generic cloud shapes. I would definitely be up for sharing the compound once its working correctly, perhaps this may be a good candidate for a community project. Evolving & billowing clouds... certainly a useful compound!
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Mathaeus
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Re: Volumetric render tests (large pics)

Post by Mathaeus » 20 Jan 2012, 22:59

Finally I got this :) Almost the same settings RRay mentioned. Density 5000, but 0.005 for shadows, to allow translucency effect. About 3 minutes for rendering on Quad Core, AA 0-1, contrast 0.1. It seems that volume rendering don't need some heavy AA filtering, as it is already sampled by "self". Probably 0-0 might be enough. Could be problem if there is some hard surface in mix, anyway.

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Maximus
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Re: Volumetric render tests (large pics)

Post by Maximus » 21 Jan 2012, 06:44

I cant get a single result off this shader...every render i do is just horrible. can someone share some settings or some basic scene? That would be awesome..

great render Mathaeus..

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Re: Volumetric render tests (large pics)

Post by rray » 21 Jan 2012, 14:00

Hey thanks for posting tests and comments!
Here's a scn file:
VolumeShaderMeshTest.zip
(106.55 KiB) Downloaded 197 times
(needs color management to be turned on in Prefs->Display)

About the cloud billowing effect, no idea if this is actually related, but I noticed in the recent Übertage video (bottom one on this page) Holger was talking about per obj spherical coordinates in his new fractal4D shader (available for free in is BA_essentials package). It might prevent the swimming effect.
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Re: Volumetric render tests (large pics)

Post by Tekano » 21 Jan 2012, 14:30

Nice test Mathaeus, an interesting looks, very coral or organic. is that a single particle at the end of each strand? maybe you should try the new spherical coordinate distortion as well to break up the uniformity of each particle a little. :D
rray wrote: About the cloud billowing effect, no idea if this is actually related, but I noticed in the recent Übertage video (bottom one on this page) Holger was talking about per obj spherical coordinates in his new fractal4D shader (available for free in is BA_essentials package). It might prevent the swimming effect.
Rray, yes! that is what I tested with the 2 renders I posted on page 1 of this thread. this was immediately after watching Holger's video, I jumped on it because that is what was needed for a pyroclastic primitive, so I think that is what the displacement was used in thoses renders, the new fractal4D shader and what I assume to be spherical coordinate distortion of each particle . Again, looks great as a still, even though it rendered a long time, but as a sequence it was dreadful with colors and particles popping all over the place. I have not tried with 5000 density though! It always seems to fail when transparencies and low total cell counts across the volume are involved, and unfortunately with clouds, transparencies are pretty essential.
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Re: Volumetric render tests (large pics)

Post by rray » 21 Jan 2012, 20:44

Yes that shader needs most settings at max for something that's ok for animation.
Increasing the density makes this shader render faster luckily. Doesn't help with fluffy clouds though.

I still don't understand the whole power lookup thing. It looks like something's travedling along a magnetic field :)
Have to look a bit more into that couldn't even find a way to control the local texture coordinates per particle, that would be useful for a start.

Here's animation test with the "billowing" preset from the particle shaper:
billowing.gif
billowing.gif (532.74 KiB) Viewed 2215 times
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Mathaeus
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Re: Volumetric render tests (large pics)

Post by Mathaeus » 21 Jan 2012, 22:43

Tekano wrote:Nice test Mathaeus, an interesting looks, very coral or organic. is that a single particle at the end of each strand? maybe you should try the new spherical coordinate distortion as well to break up the uniformity of each particle a little. :D
It's Andorian anemone, everyone in universe knows it's growing exactly in this way :). No ICE strands, just evenly distributed particles - without some especial reason for that. I've tried to get a feasible render time, mainly.

As an ICE addict, I'd always try to do as much possible with ICE, of course. BA volume works nicely with huge counts of particles, also it seems to be much faster without any texture - and preview is (almost) in real time.

But this pyroclastic primitive thing, looks like some already "artistic" implementation, and people somehow likes to be happy with just one primitive. Anyway, would be nice to play with all that stuff, one day.
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Tekano
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Re: Volumetric render tests (large pics)

Post by Tekano » 22 Jan 2012, 00:38

@ Mathaeus Andovian? wasnt that the blue guy with tentatcles from Enterprise? :D

@ rray I wanted to join the 5000 density club as well. here is a render of simple particle sim with an attempt at using biult in particle volume shader for distorting spherically a noise on each particle, in this case ba_fractal4d , this is 5k density, cell size of 1, High ambient occlusion 5.0 and low 0.05 shadows. Rendered with physical sky & FG. took a long time , over 20 mintes, sorry didnt have exact time. also tweaked it a bit in gimp afterwards as it was very noisy :ymblushing:

anyways heres a scene(2012 Sp1) attached to play with if anyone can handle 20+ minutes a frame
Attachments
clouds_shaderse.rar
(226.64 KiB) Downloaded 91 times
volume_test._tweaked.jpg
volume_test._tweaked.jpg (96.74 KiB) Viewed 2194 times
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Re: Volumetric render tests (large pics)

Post by Mathaeus » 22 Jan 2012, 19:40

Well, my "particles only" idea seems to be wrong - cells in lookup table needs to be smaller than one particle. Huge count of small particles wants a huge lookup table too.
Definitively there are a lot of parameters, able to slowdown the render. Lookup table, marching settings, evaluated dept, alpha, ray-marching quality...
Nothing new when it comes to ray-marching render, anyway.

This one is rendered with a help of nodes from BA plugin - exactly, there is a 'mesh distance' node which makes a smooth falloff, when volume shader is applied to mesh. Theoretically, something similar could be done by filling a mesh volume by particles - but I'm not sure the result is same...
No any particle for this, just a mix of animated fractals. Render time for one frame is about 40 seconds on quad core, using 3 lights with shadows, AA 0-0.
There is small camera movement too. Beside default settings, a bit of 'color absorption', stronger shadow density.

FLV with animation

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Re: Volumetric render tests (large pics)

Post by gustavoeb » 22 Jan 2012, 22:39



some time ago I tested a demo of Slipstream... I cached some stuff I did but never had the time to render it... now with thread I finally found the motivation for it.

I like the sim itself, and there was a lot of artist friendliness since you can use ICE to do anything with the particles. But doesnt matter how many particles put in (and specially with thick volumes) you can always see the individual particles... I feel like when fluids are rendered out of a voxel grid, one does get a better result.
I tried messing with the shader to change that, but no good results. I though Metaball behaivour could do the trick, but it cant...
Any thoughts?

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Re: Volumetric render tests (large pics)

Post by Tekano » 23 Jan 2012, 14:10

Hi Gustavoeb,

in other softwares for rendering something like that it would be either Krakatoa and you would increase the point count to be massive and the point size to be tiny.. or yes, some fluid / cell grid volume solver would be more desirable. it is certainly possible to get some decent look though with much less particles using the built in BA particle volume shader. open up the example scene in samples/rendering/ ICE firedragon , change the gradient that drives it to something like what you have and render.
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BA_volume_cloud_ICE_firedragon.jpg
BA_volume_cloud_ICE_firedragon.jpg (238.01 KiB) Viewed 2076 times
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Zybrand
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Re: Volumetric render tests (large pics)

Post by Zybrand » 23 Jan 2012, 15:54

Tekano wrote:
oh. BenP's blog works here from UK fine! was going to try and make the billowing stuff work as I wanted on a sphere first before trying with more generic cloud shapes. I would definitely be up for sharing the compound once its working correctly, perhaps this may be a good candidate for a community project. Evolving & billowing clouds... certainly a useful compound!
Tried BenP's blog again today and its working now :D . I would be very grateful if you share your compound once your happy with it. As far as community project goes I think its fast become one with all the responses and renders coming in.

I'm also trying to see what I can get working with the cloud primitive setup. I've got a particles looking like your first test Cube Powah v1 only on a sphere, but thats as far as I got for now.
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cloud primitive.PNG
cloud primitive.PNG (143.42 KiB) Viewed 1035 times

Falam

Re: Volumetric render tests (large pics)

Post by Falam » 04 Feb 2013, 08:25

Where do I find some of the shaders listed in this thread, some I'm highly interested in. I searched the Softimage Resource Site (RRay) which has become my only friend :) and I can't find, it's not that I don't find any information related to the shaders used in this thread, I can't find where to download them ? I personally have some BA shaders installed (SPDL) can't related to what I have installed to the shaders used in this thread ?

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