How to use point vex expression in pointwrangle sop

[sadhu]

Hi,

Noob question

I am creating a float attrib "chk" and its value is random(ptnum)

I want to crate new attrib , "a" and I want its value to be equal to value of chk attrib for point number 15

f@chk = random(ptnum);
f@a = point(".","chk",15);
printf("%f",@a);
[/CODE]

I am not getting the desired result. Can someone help me point out my mistake?

Thanks a lot for you time.

: )

[magneto]

I don't think you can access the value of that attribute because it's not created yet, let alone for point 15. You need to use 2 point wrangle sops, or create the attribute with another sop beforehand.

But if that's all you need, you could calculate the value of the attribute for point15 in your code.

[sadhu]

Hi Magneto. I tried that. I am creating "chk" attrib using attribcreate node. but still i could not bring its value for a specific point by point expression.

f@chk = random(ptnum);
f@a = point("/obj/grid_object1/attribcreate1","chk",15);
printf("%f",@a);
[/CODE]

I am learning vex. I was doing for and while loop. What I want to do actually is find out the min and max value of "chk" through these loops. So i was using loop iteration value as point number in point expression but it is not working in pointwrangler sop.

Edited June 29, 2013 by sadhu

[bloomendale]

1) i think you need to use op: fullpath in point vex func

2) you can use import func instead to avoid all these op:

and yes, magneto is right - try using 2 nodes.

[sadhu]

Hi bloomendale,

Thanks for you reply, yes with op: it started working.

f@a = point("op:/obj/grid_object1/attribcreate1","chk",15);

Can you tell me how to use import vex function?

int import(string attrib_name, type result&; int input; int pt_num)

What is type result&

import("chk", float; 0 ; 15);

[bloomendale]

you can use something like

int res;

res = import ("chk", f@a, 0, 15);

in point wrangle sop.

or just

import("chk", f@a, 0, 15);

if you don't need the result of import func (success or fail)

Edited June 29, 2013 by bloomendale

[sadhu]

Yes it is working. I have one more question.

How come it is working with comma ? It expects semicolon after type result& and int input

• 
  int import(string attrib_name, type result&; int input)
  
• 
  int import(string attrib_name, type result&; int input; int pt_num)
  
• 
  int import(string attrib_name; float values[] &; int input; int pt_num)
  

[bloomendale]

imo it's bad formatting in manual. use "," instead.

afaik ";" is end of token in vex

[sadhu]

Thanks bloomendale.