Get Closest Node

Altair Forum User

Hi,

I have a nodelist of some 5000 nodes.

I have a point (x,y,z).

Is there any way to find out closest node to the point ( x,y,z) in the defined nodelist ( i.e: among 5000 nodes and not among all nodes in model ) ?

If anyone have idea, plz reply.

Regards,

sateesh.

Altair Forum User

Hi Sateesh,

You can use hm_getclosestnode.

For further details please refer HM8.0/9.0 documentation.

Regards,

Mandar

Altair Forum User

Thanx Mandar for reply.

I tried hm_getclosestnode .

It was working on any defined set of nodes like nodes on some elems/components.

Thing is the nodelist i have to check is a set of temporary nodes .

If i use hm_getclosestnode command , it was giving a closest node in the entire model to that point but not in my nodelist.

Regards,

sateesh.

Altair Forum User

Do it on your own (tested with some 200000 nodes: took my machine half a minute):

##################################################################################                             VECTOR ROUTINES                             ##################################################################################if [namespace exists thgrVector] {namespace delete thgrVector}namespace eval thgrVector {    namespace export vexpr vcalc vnorm matmul    foreach op {+ - * / % ==} {proc $op {a b} 'expr {\$a $op \$b}'}}# thgrVector::lmap --##       lmap is a 'collecting foreach' which returns a list of its results.#       See http://wiki.tcl.tk/13920## Arguments:#	_var	name of the variable#	list	map 'body' over each item of the given 'list'#	body	tcl command to be evaluated for each 'list' element## Results:#	proc thgrVector::lmap {_var list body} {    upvar 1 $_var var    set res {}    foreach var $list {lappend res [uplevel 1 $body]}    set res}# thgrVector::vcalc --##       Do arithmetics of the form:#         * scalar @ scalar -> scalar (like expr does)#         * vector @ scalar -> vector#         * scalar @ vector -> vector#         * vector @ vector -> vector (all of same dimensions, element-wise)#       Additionally the cross and scalar product is supported#       ATTENTION: vcalc {{1 2 3} {4 5 6} {7 8 9}} * {{1 0 0} {0 1 0} {0 0 1}}} #         gives  {{1 0 0} {0 5 0} {0 0 9}}##       See http://wiki.tcl.tk/14022#	## Arguments:#	a	first vector/scalar#	op	operator (e.g. + - * / X)#	b	second vector/scalar## Results:#	Value of the evaluated expression $a $op $b.proc thgrVector::vcalc {a op b} {    set lena [llength $a]    set lenb [llength $b]    if {[string toupper $op] eq 'X'} {        # Ex-product has to be treated special        set L [concat $a $b]        if {[llength $L] != 6} {error 'ex-product only defined for dimension 3'}        foreach {a1 a2 a3 b1 b2 b3} $L {}        return [list [expr {$a2*$b3-$a3*$b2}] [expr {$a3*$b1-$a1*$b3}] \          [expr {$a1*$b2-$a2*$b1}] ]    }    if {$lena == 1 && $lenb == 1} { ;# scalar operation        $op $a $b    } elseif {$lena == 1} { ;# scalar and vector operation        lmap i $b {vcalc $a $op $i}    } elseif {$lenb == 1} {        lmap i $a {vcalc $i $op $b}    } elseif {$lena == $lenb} { ;# vector operations        if {$op eq '.'} { return [expr [join [vcalc $a * $b] +]+0] }        set res {}        foreach i $a j $b {lappend res [vcalc $i $op $j]}        set res    } else {error 'length mismatch $lena != $lenb'}}# thgrVector::vnorm --##       Vector norm - 'length' or 'size' of the vector.## Arguments:#	v	vector (list of components of the vector)## Results:#	Norm of given vector v. Value is always a floating point number.proc thgrVector::vnorm {v} {    return [expr sqrt([join [vcalc $v * $v] +]+0)]}namespace import thgrVector::vcalc thgrVector::vnorm################################################################################ diff_p_N --##       Return distance between node $NodeID and point $point.proc diff_p_N {NodeID point} {    set nCoords [join [hm_nodevalue $NodeID]]    return [vnorm [vcalc $nCoords - $point]]}# findClosestNode --##       Return node ID which lies closest to point $myPoint. Search among#       $nodeList nodes only.proc findClosestNode {nodeList myPoint} {    set mindist 1e27    set id -1    foreach nodeID $nodeList {        set delta [diff_p_N $nodeID $myPoint]        if {$delta < $mindist} {            set mindist $delta            set id $nodeID        }    }    return $id}# LETS TEST IT:*createmark nodes 1 displayedset nodeList [lsort -integer [hm_getmark nodes 1]]set myPoint {100.0 0.0 0.0}puts '[findClosestNode $nodeList $myPoint] is the closest node to point $myPoint.'