Detect Property change state

[absudario]

This is a naive approach on how to get a value from previous frame but it is returning always 0.

I want to trigger an animation after some property changes, say, from 1 to 0.

[sepu6]

Not sure exactly what you want to do here. Do you want to use this property to emit particles?  Do you have a solver prior to this that is activating points?  What is that pass node doing? 

[absudario]

I just wanted to create a fade effect, very simple.

The pass introduces a number switching from 0 to 1 every n frames. Say a 30 frames interval.

"emission" property would be immediately "1" when pass is 1. But when pass switches to "0", I wanted to "decay" the emission gradually subtracting a value from it every frame... I was trying to use "iteration", to get something simpler than what is seen on the "simulation example" node, but I am not used to the syntax here so it is taking a time to figure it out.

[sepu6]

Here is a quick example using the simulation example (which is just a solver) I put notes on the graph. Press play. 

 

[absudario]

Thank you. I will check your file.
Meanwhile I was also trying to dectect the change in state, my mistake by studing the "simulation_example" node was that the icons of state ports made me believe the node was some sort of "iteration" node. I assumed there could be a case where you delete current_index, or max_iteration on that a iteration node. This is my attemp to work around the problem - needs clean 

[sepu6]

Yeah, the iteration could be used as a solver. you can always delete the max iterations and current index if you do not need them and just create a feedback port. The simulation example just provides an easy way to create a solver which adds some nice functionality.