Point Age

[PhasmaCeritus]

Hi,

I have a quick question: how can I create an attribute in the geometry level which would measure point age.

I got stuck at outputting points creation frame number to it's custom made attribute.

Thanks

[symek]

You would have to go through pops, since sops cook geometry regardless it's current state ( x+=1 is not possible). You can simple create static particles, with age/life/custom attribute from you points and go back with them to sops. For some specific purpose chops are also in practice here, but I think pops are much more handy.

Another approach might be a sop solver dop, which can write "on a top" of a current geometry, but I'm not sure how about updating points number from sop during execution (turning on "Use Deform Geometry" is an option, but updates also attributes on existing points).

Anyway, popnet is fast and good solution.

[symek]

quick example added.

points_age.hip

[pclaes]

errr... you mean in sops?

If you are only using sops, you can't. You can however get age (or geometry with history over time) by using dops. Specifically the sopsolver can do this for you.

Or you could trigger particles to be emitted from geometry at certain points in time. Those particles will record a life attribute that records the age inside - this is in the POP context.

[pclaes]

ahhh... he beat me to it .

[PhasmaCeritus]

thanks guys!

[PhasmaCeritus]

hm, I have got the concept but could not figure it out in Houdini, sorry I am new here.

so let's say we have this line with points appearing in time (move the time slider); how do I get an age or creation frame attribute on these points?

thanks

Edited January 18, 2010 by PhasmaCeritus

[PhasmaCeritus]

that's the file I was referring to

points_age.hip

Edited January 18, 2010 by PhasmaCeritus

[junaid]

you can find here an attribute called "born", which impulses to 1 for each new born point, is this is what you want?

Cheers,

Junaid

that's the file I was referring to

points_age_02.hip

[PhasmaCeritus]

you can find here an attribute called "born", which impulses to 1 for each new born point, is this is what you want?

Cheers,

Junaid

This is awesome what you did, but I still can't figure how can I get an attribute where I could store point creation frame number permanently.

For example spreadsheet at the end should look something like this:

P___birthFrame

1___1

2___10

3___35

4___45

5___63

6___75

7___120

8___130

9___150

where P is a point number and birthFrame is a custom attribute

Edited January 19, 2010 by PhasmaCeritus