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Attribute Growth [SOLVED]


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This one is a little tricky. I have seen many tutorials showing how to expand / grow an attribute from a start point outward, but I'm struggling with expanding an animated attribute.

I have this sphere that accumulates a mask attribute over time, leaving a trail where another object has moved across the surface:
image.png.8bf5683ae348889372590a3d1e810a09.png

I'd like that mask attribute to expand / grow  outwards until it covers the whole sphere.
image.png.d4bc5558d93a8d07ef39dfcfa995190a.png

File attached:

attribute_spread.hiplc

Edited by GlennimusPrime
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Posted (edited)

Thanks @Librarian @konstantin magnus @hannes603 all really great examples!

Just to throw a spanner in the works, one pretty major issue I forgot to mention was the points I'm working with are disconnected and animated..

I managed to get @hannes603 example working on an animated static point count object by swapping the inputs of the vop inside the solver:
image.gif.b665594fb153093348429b70e53b89b7.gif

But unfortunately this does not work when I have a changing point count when working with particles - I tried copying the attribute from previous frame onto the current frame using point ID to match attributes, but the entire object is filled almost instantly with the infected attribute.
image.gif.b0bec42cf773844172590da7ee6b952b.gif

Any ideas when working with animated changing point count objects?

Updated file attached:
attribute_spread_v2_animated.hiplc

Edited by GlennimusPrime
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11 hours ago, GlennimusPrime said:

Would love to see that working please @hannes603 Your example file looks incomplete? The infection spread does not work unfortunately.

@Librarian That infection solver looks amazing, but unfortunately I'm unable to install any otls at the studio I'm working.

what do you mean it does not work . can you explain what you after ? otherwise i cant help :)

Edited by hannes603
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Posted (edited)

Right, got it! Thank you both @Librarian and @hannes603 for the multiple attempts here. Much appreciated!

 

One last thing, what if I wanted to do this as a post-sim infection spread? I'm dealing with pre-cached particles. They have an ID attribute if that helps?
I've tried multiple variations of your popvop / pointvop setup but can't seem to get it to work post sim.

Edited by GlennimusPrime
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  • GlennimusPrime changed the title to Attribute Growth [SOLVED]
On 6/23/2025 at 11:14 PM, GlennimusPrime said:

I'm unable to install any otls at the studio I'm working.

 

3 hours ago, GlennimusPrime said:

One last thing, what if I wanted to do this as a post-sim infection spread?

Studio ??? 
Talk to your manager right away and give these guys a job @hannes603 @konstantin magnus :ph34r::rolleyes: if they need a job..

Find Qiita website . !Advent Houdini 2020! you have  Files for Infect and very Nice tricks for making those effects and much more using same Logic . Then(TIP) When you have Full Code that Works in Houdini you can Make anything in chatgpt(reverse and investigete)  Now days.
Have a nice Day .:wub:
 

Infect.gif

Edited by Librarian
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Thanks @Librarian although this example is working post popnet, the number of points is static. The issue still exists of this working on a changing point count sim (post sim, not inside the popnet).

That has been the most difficult part of this process that has me stumped.

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18 hours ago, hannes603 said:

sure you can also do it post solve  pretty much the same way .. you only need to accumulate all particles in the solver and remove them afterwards.. otherwise  id hase no corrosponding ptnum:)

Amazing, that's it! Thanks so much @hannes603 Really appreciate all the effort both you and @Librarian have gone through here to tackle this one.
Goes to show the greatness of the Houdini community. Many thanks.

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On 6/27/2025 at 4:35 AM, vicvvsh said:

Hi,

changing "Max Points" parm on attribute wrangle will be able to control speed of infection spreading.

attribute_spread_v2_animated_01.hipnc 434.97 kB · 9 downloads

Apologies @vicvvsh I missed your post. This is even perfect. So simple and fast to work with. Thank you!

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