accessing a Details Attrib from the 2nd Input??

[bhaveshpandey]

Hi I have been trying to access the details attrib which I created to store the Total number of points..

I want to access this inside VOPs but am having some issues..

I want to use this value as an input to the For loop's end value..I did manage to get the Value but when I plug it into

the for loop's end value input it errors out saying bad parameter..

I tried accessing the value using Channel reference as well as by the npoints() expression but the problem

remains..

could anyone throw out a hint?

Also, while i'm at it, let me ask one more question as well

is it possible to get the Attributes in 1,2,3 inputs all at once just like from the main (0) input??

for instance: can I get all the P values inside VOPs from say the 2nd input of the VOP SOP together instead of having to specify

the point number specifically??

here's the HIP file..

thanks

test.hip

Edited December 11, 2009 by bhaveshpandey

[Ratman]

You can use the detail() function to access details data

test_details.hip

[bhaveshpandey]

hey thanks Rick...

I already tried it out with the details() expression..and it works too but

for some odd reason, the for loop is not working with that value..thats why i attached a print VOP to it to see if its working..

could you tell me if the For Loop was indeed working on your machine and the print VOP outputted some non zero value??

Edited December 11, 2009 by bhaveshpandey

[graham]

Your problem is that you put an expression as the default value, and that expression is fine if you were to use a Constant VOP to store the data, but that expression errors out at the SOP level because if you unhide the parameter you'll see that it's searching for the SOP with the data at the object level.

If you want the number of points from the 2nd input I'd just suggest using the parameter, with a default value of 0, then put in an expression along the lines of npoints(opinputpath(".", 1)). This gets the number of points from operator connected to the 2nd input.

[graham]

Forgot to attach an example.

Since there is VOP to access detail variables I just removed the AttribCreate and do it using the expression. I have both the parameter and constant setup in the file.

test.hipnc

[bhaveshpandey]

hey Graham! thanks a ton man..

thats what I needed..however I cant understand two things..

1) what does this expression mean:

npoints(opinputpath("../vex_numthreads", 1))

the npoints and opinputpath is understood but why did we put in vex_numthreads in there?

and

2) why was it needed that we added a parameter node with a default value of 0?

thanks a lot again for the solution

cheers

[graham]

I have no idea about the expression pointing to the vex_numthreads channel because I don't see that in my hip file. No idea where it came from.

The idea was that if you are going to use a Parameter VOP it's generally a bad idea to have an expression in there that is using a relative path because it's always going to have issues. Personally I'd use the constant, or just put the expression right into the for loops parameter.

[bhaveshpandey]

hey Graham..thanks a lot for taking the time ..

yes the vex_numthreads is not there in your file..I restarted Houdini and its gone now..

finally understood it..took some time to make sense out of it

thanks again..