Hello !
I’m working on a little python plugin function to improve some performances in one of my tools (moving a mel function into an API function basically). Unfortunately I’m stuck on something and I really don’t see why I get an incorrect result.
So I’m sending to my command the currently selected vertex (its index) and then compare with all the vertices in the related mesh which is the nearest vertex from this one. The result is totally incorrect, the vertex I get is really not close. On a 12K mesh (subdivided sphere for example) I can get a vertex that can be on the opposite side of the mesh.
I’m far from being fluent with the Maya API in Python unfortunately. Any help is appreciated. 
Here is the main python code :
# arguments
argData = om.MArgParser(self.syntax(), args)
index = argData.flagArgumentInt(kFroIndexF, 0) #currently selected vertex (index)
range = argData.flagArgumentDouble(kFroRangeF, 0) #max distance to find a vertex
# get the active selection
sel = om.MSelectionList()
om.MGlobal.getActiveSelectionList( sel )
list = om.MItSelectionList(sel, om.MFn.kMesh)
# get mesh
mesh = None
dagPath = om.MDagPath()
list.getDagPath( dagPath )
mesh = om.MFnMesh( dagPath )
#define variables to find the vertex
nb = mesh.numVertices()
point = om.MPoint() #target point
print ("
There is " + str( nb ) + " vertices in the mesh")
foundVtx = 0
closestVert = 0
minLength = None
pos = om.MPoint()
# search for the nearest vertex
count = 0
while count < nb :
# ignore vertex already selected by user
if count != index :
#get point by its index
mesh.getPoint(count, point, om.MSpace.kWorld)
dist = pos.distanceTo( point )
#if the vtx is the closest, save it (only if we are under the user range)
if dist <= range :
if minLength is None or dist < minLength:
foundVtx = 1
minLength = dist
closestVert = count
count += 1
if count :
print ( "Vertex found is " + str( closestVert ) + "
" )
#send the closest vertex to the user
resultArray = om.MDoubleArray()
resultArray.append( foundVtx )
resultArray.append( closestVert )
resultArray.append( point.x )
resultArray.append( point.y )
resultArray.append( point.z )
self.clearResult()
self.setResult( resultArray )
Here is how I call it (I assume that the user has selected a vertex on a mesh) :
global proc froRetopoTargetWeld()
{
string $highlighted[] = `ls -hl`;
string $sel[] = `ls -sl`;
float $range = `floatField -q -v froRetopo_field_snapweld`;
//isolate vertex index
string $buffer[];
tokenize $sel[0] "[" $buffer;
tokenize $buffer[1] "]" $buffer;
int $index = int($buffer[0]);
//select mesh to compute vertex list in the python plugin
select -r $highlighted[0];
//call the python command and get the nearest vertex index
float $result[5] = `froVertexFinder -fid $index -frg $range`;
//found a vertex ?
if($result[0])
{
//vertex name
string $target = ($highlighted[0] + ".vtx[" + int($result[1]) + "]");
select -r $sel[0];
move -ws $result[2] $result[3] $result[4] $sel[0];
select -add $target;
polyMergeVertex -d 0.2 -ch 1;
select -r $highlighted[0];
}
else
select -r $sel[0];
}