Unable to initiate pyro spread

[archz2]

I am trying to develop pyro spread beginning from top of some rock pieces using the following tutorial. 

https://www.youtube.com/watch?v=jsjx3wsdHvk

The spread gets successfully initiated if I use some spheres and their top portion gets highlighted.

 

But nothing happens when I use the rocky pieces. 

 

Moreover, in the tutorial, at 11 min 12 secs., the tutor mentioned to write 'YMAX' when the groupcreate SOP it to be connected to it. But I failed to get the desired output. However, when I wrote 'YMIN', I got the desired output. What is happening?

 

 

PYRO INJECT+VELLUM_forums.hip

Edited August 26, 2023 by archz2

[bengaet]

i could not replicate your issue, YMAX is working as expected for me.

however I replaced your grouping process with a little bit of vex

vector bbox = relbbox(0,@P);
if(bbox[1] == 1){
    @group_burn = 1;
}

 

PYRO INJECT+VELLUM_forums_2.hipnc