get a level in vex ?

[wildparky]

Hi guys!

I want to calculate a accumulated point distance from 'pt0' in the vex or vop.

i think ...

====

sop

scalarfield() {

...

for ( i=0;i<level;i++)

..

neighptnum = getneighbour(ptnum, 0, 0);

success1 = import("P", adata1, 0, neighptnum);

diff1 = P - adata1;

len = length(diff1);

vec = set(len, 0, 0);

newadata = vec;

addattribute("distlength", newadata);

if ("" != "")

addvariablename("distlength", "");

}

================================

pt4 have 3(level) neighbor (4:3-1-0)

pt3 have 2(level) neighbor (3:1-0)

pt1 have 1(level) neighbor (1:0)

=================================

How can i get a level of current point in vex ?

[wildparky]

......

0 = level 1

1 = level 2

2 & 3 = level 3

4 & 5 = level 4

[wildparky]

pt4 & pt5 => 3time ' neighbor distance ' calculation .

pt2 & pt3 => 2time ' neighbor distance ' calculation .

pt1 & pt0 => 1time ' neighbor distance ' calculation .

[Mario Marengo]

Hi Wildparky,

Hard to tell what it is you're up to exactly; except maybe a tree search (n-ary depth-first)?

But then, that would have nothing to do with distance (in the Eucledian sense); so what do you mean when you say "accumulated distance"? And how does it relate to your "levels"?

Never used the getneighbour() function before; but just scanning the docs, I noticed it says that the order of traversal is not guaranteed -- I read that as meaning that you can't count on it doing an orderly spiral outward from P. (not that that would necessarily help, if I understand you correctly).

What is it you're trying to accomplish? -- there may be other ways in which to tackle the problem.

Sorry I got no answers... just more questions

PS: This topic should maybe be moved to VEX.

-- Mario.

[David Gary]

I don't think you need to get the point-level to compute an accumulated distance.

Why not use a while loop, and increment a variable (set to 0 for the first step).

To me, the problem is more: how do you set/get the path through the mesh ( how do you choose

your neighbor?)

[AndrewVK]

Not sure. May be this helps.

sop
level()
{
  int i, tempnum, curneighbourconunt;
  int level = 0;
  int walk = 1;
  int curpt = ptnum;
  while (walk){
    curneighbourconunt = getneighbourcount(curpt, 0);
    for (i = 0; i < curneighbourconunt; i++){
     tempnum = getneighbour(curpt, i , 0);
     if (tempnum < curpt){
  curpt = tempnum;
  break;
	} 
    }
  level += 1;
  if (curpt<=0) walk = 0;
 }
addattribute("level", level);
}

[AndrewVK]

Sorry....bug fix...

sop
level()
{
  int i, tempnum, curneighbourcount, brokenmesh;
  int level = 0;
  int walk = 1;
  int curpt = ptnum;
  while (walk){
    brokenmesh = 0;
    curneighbourcount = getneighbourcount(curpt, 0);
    for (i = 0; i < curneighbourcount; i++){
     tempnum = getneighbour(curpt, i , 0);
     if (tempnum < curpt){
  curpt = tempnum;
  break;
	}
     brokenmesh += 1; 
    }
  if (brokenmesh == curneighbourcount) break; 
  level += 1;
  if (curpt<=0) walk = 0;
 }
addattribute("level", level);
}

[Mario Marengo]

Sorry....bug fix...

Hey Andrew;

Nicely done!

Now if you could do something to not have to walk all the way to pt0 for every point.... that would be the "cherry on top" . But I guess there's no way to tag points as "visited" on the fly, is there?

Wildparky: Andrew's sop is your answer. But it depends on all point numbers increasing monotonically from some root point. An L-System, for example, would have points numbered in this way automatically. But that's the kind of topology you seem to be working with so it should be OK.

Cheers!

-- Mario

[AndrewVK]

>>But I guess there's no way to tag points as "visited" on the fly, is there?

You right...its impossible

>> But it depends on all point numbers increasing monotonically from some root point.

You can fix any "crazy mesh" with help of Sort SOP (by vertex order)

[wildparky]

thanks again Andrew. and Mario Marengo

i edit something

sop

level(float min=0,max=1,rolloff=0)

{

int i, tempnum,tempnum2, curneighbourcount, brokenmesh;

int level = 0;

int walk = 1;

int curpt = ptnum;

float dist = 0;

vector cp,np;

while (walk)

{

dist.hipnc

[wildparky]

a little fix

Cd = smooth(min,max,dist,rolloff);

>>What is it you're trying to accomplish? -- there may be other ways in which to tackle the problem.

could you tell me the ways? Mario Marengo

Chris Bernardi - Shading a Coral Reef page 143 'Scalar Fields'

he used a mel script.

distx.hipnc

[AndrewVK]

Just for fun

distx3.zip