Problem in animation of instanced object

[feverheat]

I created the emitter to eject the particles & use the function of ' instancer ( replacement ) ' to instance an object to the particles. But how can I animate the object's rotation individually? i know that maybe I need to create the expression per particle, any suggestion or hint to me? Thanks !

[aries@CAVIS]

請問想用來模擬什麼東西？

[feverheat]

just like a lot of feather following in sky. Thanks ~

[aries@CAVIS]

我也曾經嘗試過但沒有深入地學、都幾煩復。
不建議使用emitter放出particles、
做幾組的particles、去連接幾個instancer比較容易控制。

令外Expression在Animation裡是有“如虎添翼”的效果、
有很多技術性方法（know how）是可以代替expression的。

[feverheat]

Thank you so much !!~~ I will go home to try & let you know the result. I will try to create the bunch of particles... But I found the porblem that if I created particles to instanced the paint effect objects, error will be appears when you render the sence. ( Maya ver. 4.5 )

[feverheat]

By the way, should I add the attribute ( vertor per particles ) ?

thank you ~
Any suggestion to this expression?

[aries@CAVIS]

先把PE的stroke和curve group起後才Instancer應沒有問題。

群體的模擬遠景使用較多、
近景的話到頭來還是需要一樣一樣地animation（如果數量不多）。
動作可以copy後修改、我想這樣做質數較好。

[feverheat]

真系唔該曬你啊！！另外，我亦有一個問題，如果我想將每一個instanced objects 隨時間轉動，有有何意見啊？其實之前問過，以下是我的朋友建議：Create an additional Dynamic Attribute with type Vector and Per
Particle.
create a Creation
expression, for example
rotationInstPP = <<0,-90,0>>;
In the runtime expression add the following line:
rotationInstPP += <<rand(0,.01),0,0>>;
You have to select the attribute under Instancer / rotation option /
Rotation...
Now the Instances will be rotated at birth and then they rotate around x with a random value...
One of the no so good things of this approach is, that you can't use the aimDirection attribute. Try to set the rotaiton in the attached scene to none...the aimDirection is quit usefull for flying things to let them look into the direction where they fly... if you wanna let them look into an direction and than add an rotation, you have to calculate it by hand...
您又覺得佢既建議okay嗎？ Thanks~~

[aries@CAVIS]

在每一組Instanced objects裡加入
runtime用的expression應該可以做到你想要的效果、
但需要先把Particle的ID取得。
“Rand”是亂數發生指令、當然rotation的亂數也能做得到。

Particle個別控制真是很“麻煩”、需要時間作研究。
我也幫不上什麼東西 、有時間時讓我好好學習一下。

[vectoreffect]

You should add a run-time expression on particle rotation. Don't add it on the aimDirection attribute.

The run-time expression may be like this:
particleshape1.rotation = <<0, frame/30 + abs(noise
(particleshape1.particleId * 303)), 0>>;

if you want difference speed on each feather, it will be:
particleshape1.rotation = <<0, frame/(abs(noise
(particleshape1.particleId * 503))*10+20) + abs(noise
(particleshape1.particleId * 303)), 0>>;

Remark: particle rotation is using radian to calculate (don't use degree to calculate).

[feverheat]

其實我有少少唔明白就是為何要用 303 & 505. 有沒有特別的意思？

[feverheat]

在每一組Instanced objects裡加入
runtime用的expression應該可以做到你想要的效果、
但需要先把Particle的ID取得。
“Rand”是亂數發生指令、當然rotation的亂數也能做得到。

Particle個別控制真是很“麻煩”、需要時間作研究。
我也幫不上什麼東西 、有時間時讓我好好學習一下。

其實我用過佢所建議我的方法，的確地可以做到這個效果，至於你所提及Particle ID的，佢亦都有講及，如果可以的話，我可以電郵他所做的給你參考？ <<但他只是把不同instanced的物件配至不同particle ID上。>>

[vectoreffect]

303, 503 are random number, no special meaning. You can use any number larger than 100.

Particle rotation and aimDirection can't use at the same time, therefore you should chose which rotation you want. Particle rotation can create a random speed and random direction. AimDirection can control the instanced objects following the tangent of the motion.

If you want the instanced objects rotation Y following the aimDirection, and rotation X following the random rotation. I can suggest a solution to you, but you should make sure the rotation X of aimDirection hasn't rotate.
- select the object, and group it.
- keyframe the rotation X of child object as loop cycle.
- select the parent object, and duplicate it.
- at least you should have ten sets of object with difference motion.
- using that ten sets of object to create instanced objects.

[feverheat]

咦…你呢個方法都幾好喎，同樣地做到同一個Random rotation既效果，thank you so much!~~

[aries@CAVIS]

＞＞如果可以的話，我可以電郵他所做的給你參考？

不用send給我了、
如果成功了的話不如談一談你的做法讓大家參考一下吧。

P.S.其實自己懶＆現在沒有時間去學。