EXPRESSIONS FOR ALL! (knowledge tidbits) - Page 3

# 31 23-01-2004 , 06:05 PM

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Creating runway lighiting effects

Well its time for a cool Particle function guys...!

A linstep function is used in conjunction with a ramp to control the rgbPP attribute of the particles color. The particles appear to "turn on" sequentially from front to back. An offset is added to the particle's age to create this effect.

creation expression:

$pos=particleShape1.position;

particleShape1.lightOffset= ($pos.z+20);

--------------------

Runtime expression:

$myAge=particleShape1.age-(particleShape1.lightOffset*.25);

particleShape1.rgbVPP=linstep (2,3,$myAge);

enjoying...!

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# 32 27-01-2004 , 07:12 AM

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Originally posted by ragecgi
Hasn't really stopped, just slowed down a bit because folks are a little busy.
It is a "sticky" thread so that way it is always at the top for reference

Feel free to post any questions, and we will see if we can help

Originally Posted by

I don't know how to create footprints on the ground.

If you have an expression for it ...

I love the thread.

tathu

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# 33 27-01-2004 , 05:12 PM

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I personaly would use blendshapes for that, but in combination with that, you might also wanna try doing it with SetDriven Keys as well maybe.

I think Mike Mckinley or even Danny Ngan know of a way to do this, so they might be better people to ask user added image

Thanks! Good luck!

Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com

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# 34 28-01-2004 , 06:23 AM

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Thanks for your response so fast, and sorry if I do harass the thread.
user added image

Last edited by tathu; 28-01-2004 at 06:28 AM.

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# 35 28-01-2004 , 03:38 PM

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No prob!

Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com

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# 36 29-01-2004 , 08:20 AM

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well if u still want to use expression then u can ......program ur geometry e.g

like:

if (your foot touches ground )
the ground should effect;

else if (if its leaving the surface)
the ground should effect;

i think u'll not be able to ...produce realistic effects with only expressions
like Rage said blendshape could help....and i think that there will be an attribute that can be keyable and can be controlled through expressions...so...give a try...u know...expression makes your scene clean from raw data that take up extra..resourse cause they excute when conditions are met......

well will be putting....expression for same type of effect soon...which produces swells in softbodies....it will be helpfull to produce perfect result...for ur scene

enjoy ....

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# 37 02-02-2004 , 07:43 PM

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A noise function is used to control the Y position of a string of particles. Arithmetic operators are used to control the amplitude, frequency and offset of the function.

1. Create an emitter with as desired parameters......

2. Create Custom Attributes as follows

a. tornodoRadius
b. tornodoTwist
c. tornodoRadiusMult

now let code:

creation Expression

particleShape1.tornadoRadius=rand (.75,1.25);

particleShape1.toranadoTwist=rand (1,3);

particleShape1.position=<<1000,0,0>>;

****

Runtime Expression

vector $pos=particleShape1.position;

float $radius=particleShape1.tornadoRadius*particleShape 1.tornadoRadiusMult;
float $speed=time*particleShape1.toranadoTwist;
float $noise=noise((time*.3)+(particleShape1.particleId* .01));

particleShape1.position=<<($radius*(sin($speed+par ticleShape1.particleId)))+$noise
,$pos.y+.1,

($radius*(cos($speed+particleShape1.particleId)))+ $noise>>;

****

and third create a ramp on tornodoRadiusMult custom attribute this ramp will be used to control its hollowness from top or bottom.....

adding source file.........check it out...!

enjoying.......!

user added image

Attached Files

tornodo.rar (5.3 KB, 1657 views)

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# 38 10-02-2004 , 03:06 PM

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hey guys, I've decided to join in the fun as well user added image

.

Let's see, for a spotlight, you attach the color to a water map, edit it as you like and then for the expression (for your new water1 texture):

water1.waveTime = time*0.2 and
water1.waveVelocity = (cos(time)+1)/2

If you put a nice fog to it, and color the water map right, you could have a cool spotlight for underwater (works very well with www.thegnomonworkshop.com 's fog light,) or the illusion of the sunlight going trough the leaves of trees when you move under them.

water1.waveTime = time*0.2 makes sure the wave texture 'moves' to the left ( because it's endless ), and
water1.waveVelocity = (cos(time)+1)/2 makes sure the number stays between the 0 and 1, so that when spotlighted, it increases and decreases, just as if waves take away some sunlight user added image

. I hope I helped! user added image

:bgreen:

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# 39 10-02-2004 , 03:27 PM

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hey thats....good

this means we all are learning.....more n more..

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# 40 10-02-2004 , 03:41 PM

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Speak for yourself... the more expressions I seem to learn, the more I forget about the rest of the world :p user added image

:bgreen: It's just like user added image

, you learn to drink more and you forget more about the rest while doing that user added image

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# 41 10-02-2004 , 06:59 PM

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thats kool

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# 42 14-02-2004 , 03:23 AM

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Hi mind-raper!

I have just test your tornado expressions and your tornado scene.
Both of them are cool!

Thanks for your two lessons in one post.

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# 43 03-03-2004 , 07:11 PM

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found a usefull bit of information on Highend while i was looking for my flower prb hope it help....

Q: I have a fast moving object going past some paintFX trees, and I want the effect of wind created by it's passage to cause realistic swaying and wind blowing the branches around.
A: If you want to simply push the trees out of the way of the fast moving object, then create a small curve, attach it to your strokes(set control curves), and make the curveAttract negative with a suitable curveMaxDist on your brushes. Group the control curve with your moving object. For a turbulent wake I would generally animate the turbulence intensity on your brushes, staggering this animation based on brush location.

Rather than using control curves, the function \scripts\paintEffects\paintCollideFunc.mel could also be modified to work.

To make paint effects collide with the camera do the following: Copy this function to your local scripts directory before modifying it. You may wish to rename both the filename and the function inside. Instead of using the distance to the origin that it currently computes modify it to use the following distance:

float $c[3] = `getAttr persp.translate`;
float $dist = $sX * $c[0] + $sY * $c[1] + $sZ * $c[2];
if( $dist > 0 )
{
$dist = sqrt( $dist );
}

This is the distance from the camera to the current segment point( providing that you have not transformed the camera as a grouped node).

You need to add this modified paintCollideFunc to the runtimeFunc on all the brushes you wish to collide with(simply put the function in your scripts directory and enter the function name in the runtimeFunc field on the brush). Note that the wireframe redraw of paint effects is substantially slower when using this function.

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