How Does One Create This Effect

[keltuzar]

I was looking at this webstie http://www.vfxhq.com/1998/armageddon_rock.html

In houdini, how would one go about doing those wavy like particle effects around the asteroid.

The same effect was done in the movie Solaris but I do not remeber the website that had it...

Can someone please advice on how to do something like this effect?

Thanks in advance

edit

I found the website

http://www.imagesavant.com/

please I know the answer might be stupid but please entertain my ignorance

thanks again

[peship]

As far as i can remember these effects where created with proprietary fuild simulator - Hookah. The system consists of two parts - simulation and rendering. It drives huge amount of particles and then render them somehow.

Not really sure how all that can be acheived with Houdini ( at least not with the default tools only ). The Interact POP applies Nuton forces between particles and can keep them togather, but dont really think this will be enough.

I think Hookah's philosophy is sort of RealFlow's perParticle springs + demons ( local PP forceFields ) or to Maya's "applyPerPoint forceFields".

not really helpfull information, sorry.

[Andz]

Here is an image I created with Chaoscope , from what i understand the software plots a series of points on screen, using additive blend mode. You can literally see it making its passes. This way it can achieve millions of points too. For the calculation of the points, it uses Strange Attractors math. That look alot like some of the images presented on that link.

arctor sent me a link on how to create grass using diferent passes. I'm a completly nobe as to Houdini, but I dont think it should be too dificult to implemente something like this.

-From what 'ive seen around in the forum, there are a lot of people here good with mathematics (seen that on the SSS thread), that could find a way to implemente Strange Attractors calculation. Or maybe for starters, see what can be achieved with with standart forces.

-Use the method of renderpasses to build a image with a limited number of particles then composite to multiply them. Using a additive transmission method, to achieve the "fluid look". Even sprites could help here.

[keltuzar]

Thanks a lot guys, I now know which direction to head to take now.

[Jason]

Thanks a lot guys, I now know which direction to head to take now.

17918[/snapback]

Jens wrote this strange attractors into a Houdini setup - and I cannot remember if he distributed it out there. Do a search for this by Anakin78z...

[anakin78z]

Jens wrote this strange attractors into a Houdini setup - and I cannot remember if he distributed it out there. Do a search for this by Anakin78z...

17921[/snapback]

http://odforce.net/forum/index.php?showtopic=1665&hl=lorenz

Yeh, I did some stuff... the otl just plots the points. The more interesting bit was building the ifd. I think I could probably apply some more interesting shaders to get a similar look to what we see in some of those purdy images you posted.

-z

[keltuzar]

wow! thanks a lot Jens!

[edward]

I think those images are much closer to fractals than any type of simulation from what I've read.

PS. Yes, if you just read the website, it hints that they're something along the lines of genetic fractals. A similar open source project:

http://www.flam3.com/

Paper on flam3:

http://www.flam3.com/flame.pdf

[Andz]

Here is what i came up with. A 90 frames animation composited into one image.

Can anyone tell me how to import 90 images and not come in as a sequence? I had to copy/paste my input OP 90 times, and change the image name one by one. DONT LAUGH

[anakin78z]

Here is what i came up with. A 90 frames animation composited into one image.

Can anyone tell me how to import 90 images and not come in as a sequence? I had to copy/paste my input OP 90 times, and change the image name one by one.    DONT LAUGH 

17951[/snapback]

That's cool man.

Have a look at the opdigits() expression to facilitate the image names for each copy. Also, you could probably set up some sort of cops file using only two file reads. I'm picturing this:

read current frame, read previous frame, comp current frame over previous frame. On the next actual frame, replace previous frame with the comped frame, and then write to the same comped frame. That way you can run through the sequence and add to the same image every frame, rather than doing it all in one huge step.

Cheers,

Jens

[malexander]

an anyone tell me how to import 90 images and not come in as a sequence? I had to copy/paste my input OP 90 times, and change the image name one by one. blink.gif DONT LAUGH wink.gif

There's a File OP chooser in Houdini which can do this really fast.

1) In a network editor, press ` (backtick)

2) Change to the dir where your images are, and turn off 'Filter Sequences of files into single entries' (icon beside the Pattern box)

3) Select all the image files (left drag, or LMB click first, Shift+LMB click last)

4) Accept!

90 File COPs will be created for you, one for each filename. To wire them all into a layer COP, put down a layer COP, then select all the file COPs, then wire the first file COP into the layer.

I normally use it for importing all of my image sequences at the beginning of a comp, but it works just as well for this.

[Jason]

Or just use the TimeFilter COP?

[malexander]

Uuh.. yes. Timefilter will work great, filtersize 90, Filter Range set to "After Current", write out frame 1. So many ways to do things, I forget ones I've written.... Thanks Jason.

[anakin78z]

here's just over 10,000 utah teapots rendered with a transparency trick to get the light buildup.

[Andz]

Thank you guys for the help, I should study first Houdinis Compositing videos before continuing into this.

[Andz]

...I should study first Houdinis Compositing videos before continuing into this. 

17985[/snapback]

Ok, here I go again. Any one knows how can i set particle size to be 1 pixel ? Not bigger, nor smaller. Just one square pixel on my screen? And no antialiazing?

[Jason]

Ok, here I go again. Any one knows how can i set particle size to be 1 pixel ? Not bigger, nor smaller. Just one square pixel on my screen? And no antialiazing?

17986[/snapback]

Maybe you could render the viewport using the flipbook tool, coz Mantra wont do that. You could try Wren too, but I doubt that'll do it.

Mmm, or the GeometryCOP?