View Full Version : VEX controlling POPs? - I am desperate!

12 December 2004, 05:48 PM
Does anyone know to use VEX nodes to create simple particle controls in POPs?
The best I have managed to come up is to create a Location POP and using a simple VEX particle node and in that node I simply add some random nodes but its makes no sense to me.... so if anyone can suggest me some good combinations of nodes to launch me off please do.... thanks in advance....

01 January 2005, 10:58 AM
hey darktding

what sorta control are u looking for?

have u tried the different POP OPs that houdini come with, because they pretty powerfull.
ive been using houdini for quiet some time and havent really needed to create too many of my own pops.

however to answer ur question,

a quick example.

create a pop op in vex, and add a --global variables-- op.
then a add a --add-- op.

connect the --global variable-- "P" output into input 1 of the --add-- op

and output the "sum" of the --add-- op into the --Output-- "P" node

P obviously stands for position. what u've basically done here is connected the current position of the particle that goes into the POP op and just piped it into the output. this network wont change anything. P = <<P.x,P.y,P.x>> + nothing

Now middle click on input 2 on the --add-- op, add a parameter.
make that parameter a vector, give it a name and a label, just for neatness sake :)
the parameter will allow u to change the value of whats being added to the position of ur particles from the actual pop under pops.

now u should have a network that takes the current position of the particles and add's a vector too it. basically P = <<P.x,P.y,P.x>> + <<new.x,new.y,new.z>>

press "u" too leave the op, name the actual vex particle op in the name vex window and POP type name. give it a cool name like "my_first_pop".

and right click on ur new pop op, click on "make type from"
just say of, it should inherit the name from the label u gave it 2 secnds ago.

go to ur pops and create a location op, and then ur "my_first_pop" will also show up, create one of those.

connect that to ur location pop and adjust ur vector entry. ie X = 1, Y = 1, Z= 0; (notice the custom label)

and uve basically created a really simple uniform field POP.

hope this gives ur a start

all the best


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