Using the expression below to emit density into the texture for the ripple effect.

string $fluidTex = "fluidTexture2D1";
float $resTex[] = `getAttr ($fluidTex + ".resolution")`;
int $vertCount2[] = `polyEvaluate -vertex "pSphere1"`;
int $randNum = `rand(floor($vertCount2[0]))`;
float $uvCoord2[] = `polyEditUV -q pSphere1.map[$randNum]`;
int $x = floor($uvCoord2[0]*$resTex[0]); // make it integer
int $y = floor($uvCoord2[0]*$resTex[1]); // make it integer
if(`fluidVoxelInfo -ib $x $y 0 $fluidTex`) {
	setFluidAttr -at "density" -xi $x -yi $y -ad -fv 5 $fluidTex;
}

I have yet to find time to learn houdini but one day! I have shared some files for others to look. Of course you can upload your files to share as well.

You can download a free version of houdini here. You can play with all the features but you would get watermark in your renders.
http://www.sidefx.com/index.php?option=com_download

Anyhow, for the time being i can’t do any heavy stuff so i decided to have fun with particles on a laptop.
Fully driven by expressions no field used.

This one is nCloth test with no debris fx..

On top of that, I was given a guide book for Houdini 2.5 a couple of years ago by a friend who never studied 3D or computer graphics before.. he said he found it in local book store.. what is the chance of finding such a rare material!?!? I must be destined to learn it!

Unfortunately, my hard drive died the other day and lost my script(s).. Anyhow the script I previously wrote had a disadvantage that renamed images could never be ordered ordered based on time taken. It ordered images based on date taken but the number suffix at end was not too accurate to be able to order them as I wanted.

So I rewrote the script. This is what it does now. Instead of giving images number suffix, I decided to give each image an unique number by adding hour-minute-second eg)062534 means that the image was taken at 6am 25mins 34 seconds.

Note! Time in my camera was like 8 hours early! So that’s why the photo in the screenshot above was taken like at 2am! We were sleeping then! I have corrected time in my camera now.

Download:
http://daisukemaki.com/scripts/renameBasedOnDatesTaken.py

Usage:
- requires EXIF.py in the same directory as this script
- in shell type, renameBasedOnDatesTaken.py soccer
Image in the directory will be renamed to like this
2009-12-20.123454.soccer.JPG
2009-12-20.123625.soccer.JPG

Usage:
1. select a polygon then run the script
2. you can type in the following in python, faceExtrude(1,200,1)
faceExtrude(1,200,1) # first argument is first frame, 2nd is the end frame then the 3rd is how much of total faces should be extruding in each frame. Value of 1 is max.(1 = 100%)

import maya.cmds as cmds
#cmds.polyExtrudeFacet( 'pCube1.f[1:2]', 'pCube1.f[3:4]', kft=False, ltz=2, ls=(.5, .5, 0) )
# what percentage?, for how many frames
def faceExtrude (minTime, maxTime, ratio):
	if ratio > 1:
		print "Warning: please keep the 3rd argument to be smaller than 1.0"
	else:
		mySel = cmds.ls(sl=True)
		for fr in range(minTime, maxTime):
			cmds.currentTime(fr, edit=True )
			faceToVertex = cmds.polyInfo(mySel[0],faceToVertex=True)
			faceCount = len(faceToVertex)
			print (str(faceCount)+' faceCount')
			faceExtrudeCount = int(faceCount * ratio) # number of faces that will be extruded
			print (str(faceExtrudeCount)+' faceExtrudeCount')
			faceExtrudeCountInc = 0
			while faceExtrudeCountInc < faceCount:
				faceExtrudeCountInc += faceExtrudeCount
				faceExtrudeCountExtra = faceExtrudeCountInc + 1
				print (str(faceExtrudeCountInc)+' faceExtrudeCountInc')
				test = (mySel[0]+'.f['+str(faceExtrudeCountInc)+':'+str(faceExtrudeCountExtra)+']')
				#cmds.polyExtrudeFacet( test, kft=False, ltz=2, ls=(.9, .9, 0) )
				cmds.polyExtrudeFacet( test, kft=False, ltz=10, ls=(.3, .3, 0) )

Here is my test. I basically created a circle that emits particles, and have added more expressions to get the shape and motion.
However, with this method it may be difficult to adjust/animate the shape if a director wants a tornado shape at a chosen frame.