iterate over certain points

[amin.khormaei]

I have this code below:

i[]@TP = neighbours(0,0);
foreach(int i ; @TP)
{
    @P.y = 1;
}

how can I tell Houdini to just move the points insideTP array?

foreach move all the points.

[animatrix]

Hi,

You can do it using a detail wrangle:

int pts [ ] = array ( 1, 3, 4 );
foreach ( int pt; pts )
    setpointattrib ( 0, "P", pt, 1 );

 

[amin.khormaei]

your code doesn't work

[fsimerey]

int pts [ ] = array ( 1, 3, 4 );
foreach ( int pt; pts ) {
      vector _P = {0,1,0}; // Create a vector
      setpointattrib ( 0, "P", pt, _P ); // Here all points would get the same position : _P -> (0,1,0)
    }

{} are missing, and attrib P is a vector, so you must put a vector and not a single integer.

In your case, if you want only change P.y on those points:

int pts [ ] = array ( 1, 3, 4 );
foreach ( int pt; pts ) {
      vector _P = point(0, "P", pt); // Get P attribute of point pt
      _P.y = 1.0;
      setpointattrib ( 0, "P", pt, _P );
    }

 

Edited September 15, 2020 by fsimerey

[vicvvsh]

  On 9/15/2020 at 11:51 AM, amin.khormaei said:

I have this code below:

i[]@TP = neighbours(0,0);
foreach(int i ; @TP)
{
    @P.y = 1;
}

how can I tell Houdini to just move the points insideTP array?

foreach move all the points.

Expand  

Try this:

i[]@TP = neighbours(0,0);
foreach(int i ; @TP)
{
    if(i == @ptnum) @P.y = 1;
}

 

[animatrix]

  On 9/15/2020 at 12:26 PM, amin.khormaei said:

your code doesn't work

Expand  

I tried it before posting, it works fine. Can you post what error are you seeing?

  On 9/15/2020 at 12:59 PM, fsimerey said:

int pts [ ] = array ( 1, 3, 4 );
foreach ( int pt; pts ) {
      vector _P = {0,1,0}; // Create a vector
      setpointattrib ( 0, "P", pt, _P ); // Here all points would get the same position : _P -> (0,1,0)
    }

{} are missing, and attrib P is a vector, so you must put a vector and not a single integer.

In your case, if you want only change P.y on those points:

int pts [ ] = array ( 1, 3, 4 );
foreach ( int pt; pts ) {
      vector _P = point(0, "P", pt); // Get P attribute of point pt
      _P.y = 1.0;
      setpointattrib ( 0, "P", pt, _P );
    }

 

Expand  

1. {} is not needed in my code. Look here for similar C style syntax rules: http://www.cplusplus.com/forum/beginner/180452

2. You don't need to provide a vector type. VEX will automatically cast 0 into a vector.

[fsimerey]

  On 9/15/2020 at 11:51 AM, amin.khormaei said:

I have this code below:

i[]@TP = neighbours(0,0);
foreach(int i ; @TP)
{
    @P.y = 1;
}

how can I tell Houdini to just move the points insideTP array?

foreach move all the points.

Expand  

 

  On 9/15/2020 at 4:22 PM, animatrix said:

2. You don't need to provide a vector type. VEX will automatically cast 0 into a vector.

Expand  

In the case of Amin, he seems want to move in Y axis. In your example the 1 give a vector (1,0,0), so moving along X axis AND ALL points are at the same position (1,0,0)...

Good to know for C style syntax

Edited September 15, 2020 by fsimerey

[animatrix]

  On 9/15/2020 at 4:32 PM, fsimerey said:

 

In the case of Amin, he seems want to move in Y axis. In your example the 1 give a vector (1,0,0), so moving along X axis AND ALL points are at the same position (1,0,0)...

Good to know for C style syntax

Expand  

No, 1 will become (1,1,1).

I just posted an example. He should be able to adapt it to his needs.

[fsimerey]

  On 9/15/2020 at 4:44 PM, animatrix said:

No, 1 will become (1,1,1).

Expand  

It's not correct. See attached file.

vector(1) give a vector of (1,1,1)

Edited September 15, 2020 by fsimerey

[amin.khormaei]

thank you for all answers. the simplest way was:

i[]@pts = neighbours(0,0);
foreach(int i ; @pts)
{
    if(i == @ptnum)
    {
        @P.y = 1;
    }
}

 

[anim]

  On 9/15/2020 at 5:08 PM, amin.khormaei said:

thank you for all answers. the simplest way was:

i[]@pts = neighbours(0,0);
foreach(int i ; @pts)
{
    if(i == @ptnum)
    {
        @P.y = 1;
    }
}

 

Expand  

if your array is not varying per point (at least from your example) and you still want to use Point wrangle instead of detail you can simplify your code further to 

int pts[] = neighbours(0,0);
if(find(pts, @ptnum) >= 0) {
        @P.y = 1;
}

or @P.y += 1; if you want to offset them instead of hardcode to 1