About Breaking Objects Tutorial

Joined: 08 Jun 2007 Posts: 2 Location: Milano Italy

Hi, I'm a newbie about Houdini (normally I use xsi), but it's very intresting and I've started the Breaking Objects Tutorial and bought the dvd of procedural city!

BUT during the tutorial, he's using an expression who I've wrote but not work
I've the last free version of Houdini

The expression is applied to delete node for pick automatically the groups of points from previous partition, the expression is:
'arg(primgrouplist("../partition1")'
and it's not work!

Thanks for help!

Joined: 15 Nov 2006 Posts: 29

Hey,

Well, you should watch the tutorial again, the expression is not

'arg(primgrouplist("../partition1")'

but

'arg(primgrouplist("../partition1"),1)'

( this looked like an error of syntax anyway)and in the rest of the tut, 1 is replaced by a varying number which returns the nth group.
arg takes as arguments
1) a list(string) S
and
2) a number N
and returns the Nth element of list S
(here the list of groups returned by primgrouplist
one useful expression often associated with arg is argc which returns the number of elements in the list.

Hope it helps!
Feel free to ask questions here.
-d

Joined: 08 Jun 2007 Posts: 2 Location: Milano Italy

yes, sorry I have mistaken to write expression, I've it with the 1 after all.

But it's not work again, the final result is:
'arg(primgrouplist("../partition1"),param("primnum",0))'

in any case I've the delete node with an error and it show me nothing in the viewport!

thks! Smile

Joined: 15 Nov 2006 Posts: 29

well, without looking at the tut in much detail right now i can already say that the pb probably comes from the param expression which is no longer valid in Houdini. You have to replace it with the stamp expression which takes an additional parameter ( the path of the sop that generates the stamped parameter ) Please take a look at the Houdini help to have more detail on the syntax.