What's the best way to sum attribute values up to current point?

[magneto]

Hi,

I have a point attribute that's a float and I want to sum their values for each point but up until the current point, so like:

ptnum - value

0 - 3

1 - 2

2 - 6

3 - 5

4 - 1

5 - 7

6 - 2

So their values would be calculated as follows:

0 -> 3

1 -> 3 + 2 = 5

2 -> 3 + 2 + 6 = 11

3 -> 3 + 2 + 6 + 5 = 16

etc

Is there a quick and elegant way to do this? Or do I have to use 2 foreach sops?

Thanks

Edited October 14, 2012 by magneto

[bloomendale]

You can use For loop in VOP SOP.

[rdg]

I'd try expressionChop and would probably fail.

[bloomendale]

here is example using vop sop.

3ak_sumuptopoint.hipnc

Edited October 14, 2012 by bloomendale

[kgoossens]

Use a combination of a delete node/range and an attribute promote set to sum.

Summation.hipnc

[magneto]

Thanks alot guys, I don't know much about chops, but kgoossens, you need to use a foreach in your example, right? That's similar to how I ended up doing.

@bloomendale, your solution is also pretty compact so I might use that

[kgoossens]

Thanks alot guys, I don't know much about chops, but kgoossens, you need to use a foreach in your example, right? That's similar to how I ended up doing.

No, no for each has been used. did you check the file?

the summation happens in the attribute promote, so you'l find the value it in the prim attribute

Edited October 14, 2012 by kgoossens

[magneto]

Yes I did, I saw the prim attribute but there was no foreach sop inside

I am not sure how you can repeat this for each point without the foreach sop, that's why I asked.

[kgoossens]

Yes I did, I saw the prim attribute but there was no foreach sop inside

I am not sure how you can repeat this for each point without the foreach sop, that's why I asked.

Okay, my bad. I misread what you needed.

[magneto]

Np man

[edward]

Geometry CHOP -> Area CHOP -> Channel SOP ?

[magneto]

Thanks Edward. I tried to do it but not sure how you can solve it with chops. Would you really be able to accumulate attribute values like I described?

Edited October 16, 2012 by magneto

[Darric]

It takes a little bit more than in his post, but it works. Nice idea, Edward.

sum.hip

Edited October 17, 2012 by Darric

[bloomendale]

It takes a little bit more than in his post, but it works. Nice idea, Edward.

Quickiest way as it seems, especially if replace attribcreate with vopsop.

[magneto]

Thanks guys, I get it now. Very interesting stuff

[ben]

The same in python.

Of course it's way slower than the chop et vop versions.

sum.hip

[zarti]

It takes a little bit more than in his post, but it works. Nice idea, Edward.

thanks for transnoding Edward's post .

anyway CHOPs solution isnt as accurate as thePython method ..

not sure Why? but i do not have time to investigate actually .

The same in python.

Of course it's way slower than the chop et vop versions.

your scene / otl doesnt open in my H11

, so i wrote few lines myself and it works perfectly .

and fortunately for my case speed isnt an real issue .

.cheers