int npoints(string filename)

[wateryfield]

I stuck with a simple VEX question.

I have to get the npoins of a geometry use attribute wrangle.

 

int npoints(int input_number)  really do well.

but i was confused with the second expression.

• int npoints(string filename)

• Returns the number of points for all primitives in the geometry file. 

 

How to use it.

Thanks.

[magneto]

You can pass @OpInput1, etc.

[ranxerox]

 it for using the op: syntax.  I've attached an example.

 

 -G

[ranxerox]

 yes or that.  @OpInput1 is equivalent to `opinputpath(".",0)`.

 

 -G

 

 

You can pass @OpInput1, etc.

[Skybar]

i@mypoints = npoints(0);

That creates an attribute with the value of how many points the first input to your wrangle has. To use the second input, npoints(1) and so on.

 

Not sure if it works in a wrangle, but as a normal expression with the one that requires a string, you typically do:

npoints("../sphere1")

[ranxerox]

 sorry the file didn't attach .. here it is.  Relative references are supported now but you still need to use the "op" syntax.

 

 -G

attribwrangle_npoints.hip

[wateryfield]

Guys.

Thanks for all. 

 

• i@np = npoints("op:/obj/geo1/OUT");

the "op" syntax works well.

[wateryfield]

 sorry the file didn't attach .. here it is.  Relative references are supported now but you still need to use the "op" syntax.

 

 -G

Another question .

 

How the addvariablename  work?

 

int s = npoints(@OpInput1);

addvariablename("s", "S);

 

or

 

i@s = npoints(@OpInput1);

addvariablename("s", "S");

 

seems not working at all.

[anim]

it's the latter

just note that addvariablename() function works only with point wrangle, not attriwrangle

[wateryfield]

it's the latter

just note that addvariablename() function works only with point wrangle, not attriwrangle

Thanks. working well.

Is it any different between the point wrangle and attribute wrangle run over point.

I don't get any useful information form help card.

[ranxerox]

Thanks. working well.

Is it any different between the point wrangle and attribute wrangle run over point.

I don't get any useful information form help card.

 

 it can definitely be confusing..  Attribwrangle runs in CVex context,  pointwrangle runs in SOP context see :

 

http://www.sidefx.com/docs/houdini13.0/nodes/sop/attribwrangle

 

 the main difference is that in Attribwrangle you can add geometry (points, prims etC), which you can't in a point wrangle.  Also the functions to access geometry are different as you've discovered.

 

 -G