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Vellum Balloon Inflate controlled by an attribute problem

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JoseMarquez
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2 posts
Joined: April 2022
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Hello everyone,

I'm quite new with houdini and I'm trying to make a simple animation where I control the inflation of a balloon by an attribute.

In this case the setup is quite simple. I copy some sphere onto a grid, and control the color attribute by the distance treshold on the attribute transfer node.


Then I remap this attribute and change the name to "inflate_value"



After the vellum set-up I tried to change the value on rest length scale to the name of the attribute, but didn't make it work. I also tried VEX to assign restscale to the name of the attribute but didn't work either.



How would you do it? Attached is the file.

Thanks in advance!

Attachments:
Vellum_inflate_test_color.hiplc (502.1 KB)

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Enivob
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Joined: June 2008
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Before your copy to points, set up timing and inflation ranges.
// Set inflation range.
f@rl_start = 1.0;
f@rl_end = 3.0;
i@color_id = @ptnum;
// Randomly choose start and end frames for each sphere.
i@start = int(fit01(rand(@ptnum),6,36));
i@end = i@start + int(fit01(rand(@ptnum+801),6,36));

Then inside the solver, use a Vexpression to deploy the restlength at the appropriate time.
// Fetch attributes as local variables.
int start = point(2,"start",@ptnum);
int end =  point(2,"end",@ptnum);
float rl_start = point(2,"rl_start",@ptnum);
float rl_end = point(2,"rl_end",@ptnum);

// Supply varying restlength.
restscale = fit(@Frame,start,end,rl_start,rl_end);
Edited by Enivob - Aug. 18, 2024 12:39:56

Attachments:
vellum_rnd_inflate.gif (538.7 KB)
ap_Vellum_inflate_test_color.hiplc (493.7 KB)

Using Houdini Indie 20.5
Windows 11 64GB Ryzen 16 core.
nVidia 3060RTX 12BG RAM.
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