Hi, i'm triing to get my head around this…

I have a curve geo where i want to refine exactly by a factor of two.

but this don't work:

1. putting $NPT in division U of the refine SOP
-> won't work…

2. attribcreate -> primitive -> $NPT in Value (works now) then going to a local variable NUMTOTAL.
getting $NUMTOTAL on division U of the refine SOP don't works too…

first, why 1) don't works ??? and secondly how can i make it works ?

Thanks !

Because local variables are not supported everywhere in Houdini. $NPT is not local variable for refine SOP.
Use this expression instead:
npoints(opinputpath(“.”, 0))

ok=…

since i'm in the learning section what do you recommends about learning houdini, i'm totally lost between different formating of expression and variables…

since you write me expression code maybe i should learn that directly instead ?

If you want to get a handle on SOPs and geometry, look to each operator's help.

Many SOPs do support local variables. These specific SOPs will have a list of local variables supported by that SOP within it's own parameter fields.

Many SOPs also have example files to give you ideas as to how to use that node.

This used to drive me nuts (still does sometimes), i.e., what a parameter is expecting, e.g., HSCRIPT, VEX, local, etc. I love the VEX snippets boxes. They want VEX. I wish all the parameters were that clear about what they need.
I also wish there were more clarity in the help files about what each node expects, e.g., this node operates on points, this node expects a volume, etc.
My 2¢ worth, k

This used to drive me nuts (still does sometimes), i.e., what a parameter is expecting, e.g., HSCRIPT, VEX, local, etc. I love the VEX snippets boxes. They want VEX. I wish all the parameters were that clear about what they need.
I also wish there were more clarity in the help files about what each node expects, e.g., this node operates on points, this node expects a volume, etc.
My 2¢ worth, k