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 Dynamics & Special Effects Maya Particles, nDynamics, Fluids, Rigid Bodies & General VFX

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 03-05-2003, 05:57 PM #1 mind_raper Registered User   Join Date: Nov 2002 Location: Pakistan Posts: 57 EXPRESSIONS FOR ALL! (knowledge tidbits) Sorry to break-in mind-raper, but I'm making this thread STICKY so it will always be at the top for everyone to learn from! Post your particle/dynamics EXPRESSIONS here for everyone to learn from! Please write a little "how-to" along with your expression, so we will all know how to try it, and experiment with applying it to our dynamics/particle scenes! Thanks all! THREAD STARTS HERE first post by mind_raper here's a little nice expression to .. colorize you particles system, i have learnd it from gnomon workshop well its really good & ... is very simply first from general options add per particle attribute the rightclick---> write creation expression:: take ur your are particle shape node (particleShape1) and add per particle attiribute (rgbPP) and then assign a random value b/w (minVector i.e <<.3,5,7>>) and (maxVector i.e <<.5,7,1>>). select the render type streaks or multi-streaks or what ever u want check on the color Accum button and the lightining button too play around the values to see different color effects... particleShape1.rgbPP = rand(<<.3,5,7>>,<<.5,7,1>>); hope u find it usefull enjoy - -> :banana: __________________ Learn the Rules|Then| Burn the Rules Book
 03-05-2003, 06:25 PM #2 ragecgi Registered User     Join Date: Sep 2002 Location: Minnesota, USA Posts: 3,709 Thanks mind-raper! I think everyone should know the power of using expressions with particle systems, and your post will help others "EXPERIMENT" and learn, rather than be affraid, or overwhelmed. Good job m8! __________________ Israel "Izzy" Long Motion and Title Design for Broadcast-Film-DS izzylong.com
 03-05-2003, 06:44 PM #3 ragecgi Registered User     Join Date: Sep 2002 Location: Minnesota, USA Posts: 3,709 Here is a little expression tidbit from me to help this thread along: TO RANDOMIZE STUFF: selectedObjectname.tx = rand(-10,10); "tx", or whatever, is the attribute you can choose to have the expression applied to. So, for random particle ROTATION: selectedObjectname.rotX = rand(0,360); selectedObjectname.roty = rand(0,360); selectedObjectname.rotz = rand(0,360); Try this as a CREATION expression, AND then try it as a RUNTIME expression to see the difference between these calculation types __________________ Israel "Izzy" Long Motion and Title Design for Broadcast-Film-DS izzylong.com
 08-05-2003, 06:07 PM #4 mind_raper Registered User   Join Date: Nov 2002 Location: Pakistan Posts: 57 Speed, Stuff i think that was difficult... well no prb.... tell u one thing....they are very easy just u need little bit of understanding......here's one more example from maya's documentation! moving the particles..... Use the Particle Tool to place a collection of particles in the workspace. You then create the following creation expression to control their velocity: particleShape1.velocity = <<0,1,0>>; All the particles move in a Y-axis direction at one grid unit per second as the animation plays. explaination "particleShape1" is the shape node for ur particle object that can be anything that u have named "velocity" is the attirbute for shape node. "<<0,1,0>>" is the value for X, Y, Z Respectivly try to change the values and make it more dynamic with coditional statments like if frame==something move in X direction or the way u wanted. hope this works for u ....! enjoy coding...! __________________ Learn the Rules|Then| Burn the Rules Book Last edited by mind_raper; 09-05-2003 at 07:31 PM.
 20-05-2003, 08:04 AM #5 mind_raper Registered User   Join Date: Nov 2002 Location: Pakistan Posts: 57 Kill particles a few moments after they reach a specified locator create an emitter and a locator and create another locator first select the particle and shift select the 1st locator goto --- > Particles -- > goals--option reset the setting and press ok do the same with other locator Animate the particle from one locator to another using Goalweight attribute then add the following script and see the magic of expressions thanks for the cool expression << Daniele Tosti >> vector \$partPos = particleShape1.position; if (\$partPos > locatorName.ty) { particleShape1.lifespanPP = rand (5); } else { particleShape1.lifespanPP = 5 ; } enjoy coding :banana: __________________ Learn the Rules|Then| Burn the Rules Book Last edited by mind_raper; 20-05-2003 at 08:07 AM.
 02-07-2003, 01:40 PM #6 mind_raper Registered User   Join Date: Nov 2002 Location: Pakistan Posts: 57 Attribute of an object at a certain “offset" This expression will take the attribute of an object at a certain “offset” time, and apply it to another objects attribute. For instance it will take it off a cubes translateZ attribute, and assign it to a spheres translateZ attribute. -Create a new scene. -Create a polyCube. -Create a polySphere. -Translate the sphere about 10 units in Y. -Open the Expressions editor, then Select Filter/By Expression Name. -Type in the following: int \$offset = 10; int \$currentTime = `currentTime -q`; \$offsetTime = \$currentTime - \$offset; \$cube1Zpos = `getAttr -t \$offsetTime pCube1.tz`; pSphere1.translateZ = \$cube1Zpos; -Hit Create. and here is the explaination ! //Time offset expression //offset length (in frames) int \$offset = 10; //Get current time int \$currentTime = `currentTime -q`; //Substract the offset to the current time //so if current time is 10, //and offset is 2, offsetTime will be 8 \$offsetTime = \$currentTime - \$offset; //Get the value of pCube1.translateZ //at frame \$offsetTime (8 in our example) \$cube1Zpos = `getAttr -t \$offsetTime pCube1.tz`; //Assign it to pSphere1.translateZ pSphere1.translateZ = \$cube1Zpos; This could be taken much further, you could for example setup joints and IK so it looks like power tubes are going from the mothership to the children, you could also add a custom attribute called “motion” and multiply the “noise” section of the expression by it, so that if you decide to turn you noisy motion off you would just have to set the custom attribute to 0. You could keyframe that attribute so you could control the random “floating” motion of the ship throughout the scene so it stops looking as if it were floating if it lands for example. This type of setup could also be applied to a cranefly, or any other type of futuristic flying object etc. Experiment with setting all sorts of different relationships etc until you are comfortable with this expression. this is very handy little snippet from Oliver Shyal Beardsley thanks alot for .......it hope you enjoy it........... __________________ Learn the Rules|Then| Burn the Rules Book
 03-07-2003, 03:06 AM #7 schmick Registered User   Join Date: Apr 2002 Posts: 222 Nice thread here, i know i'll be learning from it, just hope it sticks
 03-07-2003, 12:06 PM #8 brian_ellebracht Registered User     Join Date: Oct 2002 Location: St. louis Mo Posts: 1,580 Wow nice thread THis is a really good idea brian __________________ Please check My (old) website!
 03-07-2003, 02:38 PM #9 ragecgi Registered User     Join Date: Sep 2002 Location: Minnesota, USA Posts: 3,709 It can only get bigger __________________ Israel "Izzy" Long Motion and Title Design for Broadcast-Film-DS izzylong.com
 04-07-2003, 08:14 AM #10 mind_raper Registered User   Join Date: Nov 2002 Location: Pakistan Posts: 57 yes absolutly ! Cause expression makes ur animation look more healthy and realistic support is all needed...! __________________ Learn the Rules|Then| Burn the Rules Book Last edited by mind_raper; 04-07-2003 at 08:16 AM.
 04-07-2003, 08:35 AM #11 kbrown Moderator     Join Date: Sep 2002 Location: London, UK Posts: 3,198 Here's a little tip. If you use the seed() function you can be sure your expression with rand() functions run always the same way. Code: ```{ seed(1234); float \$foo = rand(-5, 5); }``` The \$foo will contain a random value, but it is allways the same in a given frame... __________________ Kari - My Website - My IMDB Do a lot, Fail a lot and Learn a lot!
 04-07-2003, 04:03 PM #12 ragecgi Registered User     Join Date: Sep 2002 Location: Minnesota, USA Posts: 3,709 Cool K!! __________________ Israel "Izzy" Long Motion and Title Design for Broadcast-Film-DS izzylong.com
 06-07-2003, 06:31 PM #13 mind_raper Registered User   Join Date: Nov 2002 Location: Pakistan Posts: 57 Removing linear breaks Moving a turbulance field with object the problem is.. noise patterens move slong with it if u we want remove linear breaks we use turbulance phase attribute let say you....want to move a turbulance field...through particles and want to.... effect its nearest as u know turbulance field is not good at moving, thats why to aviod that we use phase as per need Example script : turbulance field.phaseX = times * 4; play wid it.... it really handy in particle system..! enjoying coding..! __________________ Learn the Rules|Then| Burn the Rules Book
 06-07-2003, 11:12 PM #14 ragecgi Registered User     Join Date: Sep 2002 Location: Minnesota, USA Posts: 3,709 Rock on m8! __________________ Israel "Izzy" Long Motion and Title Design for Broadcast-Film-DS izzylong.com
 16-07-2003, 12:11 PM #15 mind_raper Registered User   Join Date: Nov 2002 Location: Pakistan Posts: 57 Some Handly Little Expressions Rotating Wheels of Car or anything Wheels on a car: apply to the wheel rotate in z channel wheel.rz=car.tx/(2*3.145) * 1*360; Wind shield wipers Windshield wipers: apply to the wiper rotate in x channel wiper.rx = (sin (.9 *time)*45)+10; wiper = wiper sine = sine speed = how much fast you want() here i have put .9 time = time degree = i put (45) offset for position i put (10) Random Imbedded Sin Waves for a Random Effect ty = sin (sin (.5 * time) * time); enjoy ~ ! __________________ Learn the Rules|Then| Burn the Rules Book
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