emitters and expressions

[RickToxik]

Hi,

 

  so I am new in Houdini and I am trying to deliver my shot now haha.

 

  I have a FLIP setup with a custom emitter, and I am trying to animate the emission with expressions and (animated) custom attributes coming from the geo emitter...  So my questions are:

 

1) how can I use a noise() expression in the y scale of my emitter only?  Coming from Maya, I was using noise(time) all the time but can only use rand($F) in houdini right now

 

2) can a POP source use a custom attribute coming from the geo of the emitter, created with Attribute Create?  I read my local variable on the emitter but can't use it

 

I can't work with VOPs currently, it's a little bit too complicated, as it's my first houdini scene.  I've tried but can't make it do what I want.

 

Thank you!

[pbarua]

1) how can I use a noise() expression in the y scale of my emitter only?  Coming from Maya, I was using noise(time) all the time but can only use rand($F) in houdini right now

 

 

Use CHOPs to do that or noise() function. Equivalent of time in Houdini is $T. rand() gives you values between 0 and 1. Use fit01() to remap values. 

[pbarua]

2) can a POP source use a custom attribute coming from the geo of the emitter, created with Attribute Create?  I read my local variable on the emitter but can't use it 

 

 

Yes, if you specify Inherit Attributes under Attributes tab of POP Source.

Edited March 4, 2015 by Pradeep Barua

[pbarua]

If you can't understand expressions then use manual keyframes. There is no side effects of it only thing it's not procedural. 

To use CHOPs in a parameter, right click > Motion Effects and choose presets fron dropdown.