turn pop wind activation on/off based on frame number

[playfight]

Hello

I'm trying to turn a pop wind object on/off. I first tried to just keyframe it, but then I get smooth values between 0 and 1 and all i want is on and off. 

I then noticed there is a handy 'use VEXpressions' box in there. but I do not know how to access 'Activation'.

The editor does not like Activate, Active, Activation, with or without an @ Symbol. The SideFX help pages seem to indicate this is possible, but without showing how to do it.

https://www.sidefx.com/docs/houdini/nodes/dop/popwind.html#parameters

 

This is what I tired:

if(@Frame == 1 || 20) {
@Activate = 1;

}

if(@Frame == 10 || 30) {
@Activate = 0;

}
 

 

 

[Ziyad]

Hello,

You can type your expression  straight into the activation parameter, the activation value will be 1 if the condition you put is true and 0 if it's false. For example the expression below will result in the wind being activated for the first 30 frames only 

 

[dleonhardt]

When dealing with "use VEXpressions" boxes, the node will expect the name of the parameter, not the label, without an @. 
 

In your case this would be 

if(@Frame == 1 || 20) {	activate = 1; }

To find out the name of a parameter, you just hover over the label and it'll say "Parameter: name_of_the_parameter"

[playfight]

thanks Ziyad, I thought of doing this but abandoned it because I wasn't sure if I could have a more complex logic statement in there for turning it on/off. I guess it would work if I just wanted it to be turned on at a certain frame. Or can you put more complex statements (like something with curly braces) in a box like that? I will try it sometime and see.

dleonhardt - I thought I had already tried this, but sure enough, I type it out once again as you have indicated here, and it works! 

I didn't know about finding those parameters by hovering over the label, but I did stumble upon 'activate' as the name (which I why I thought I had tried it) by peering inside the Edit Parameter Interface.

but that is a good tip to remember, much faster than opening up the interface. 

Now I'm wondering if it is possible to access the wind X velocity with windx (like windx = 10)  I'm trying it now - no errors, but its not procing results either. It could be due to some other setting like amplitude or gravity, etc.

thank you both for the excellent suggestions and speedy responses