Find the longest edge of a triangle primitive and sort points on that.

[Smicksus]

Hi there,

I'm working on a setup where I need to find the longest side of a triangle and sort the points based on that.
Can someone help me out here with the vex?

I've attached an image what needs to happen:

- I have triangle with random point order from 0, 1, 2. (eventually in a for each primitive with lots of triangles)
- I need the point order to be 0 and 1 on the longest edge and 2 needs to be on the remaining point.

I've attached a simple hip scene for practice.

Thanks in advance for the help! This would help me a lot

 

Traingle_sort_debug.hip

[animatrix]

Hi,

You can write some VEX in a Primitive Wrangle SOP like this:

int pts [ ] = primpoints ( 0, @primnum );
vector pos [ ] = array ( );

foreach ( int pt; pts )
{
    vector p = point ( 0, "P", pt );
    append ( pos, p );
}

int closed = primintrinsic ( 0, "closed", @primnum );
if ( closed )
{
    append ( pts, pts [ 0 ] );
    append ( pos, pos [ 0 ] );
}

int count = len ( pts ) - 1;
for ( int i = 0; i < count; ++i )
{
    float s = distance2 ( pos [ i ], pos [ i + 1 ] );
    setpointattrib ( 0, "length", pts [ i ], s );
}

Then sort points using the length attribute with a Sort SOP, and make sure to turn on Reverse Point Sort.