odd behavior of carve / pscale

[Valent]

Greetings, 
I made a set of lines, assigned a random pscale attribute to points on one side of the lines. I copied spheres to the points, then I promoted pscale to the lines as a new attribute, then used that attribute to drive carve_SOP. But when I modify the attribute driving carve it modifies not only carve(first U) but the scale of these spheres as well.

carve_q.hipnc

[Atom]

That is correct, the CopyToPoint is interpolating that random pscale assigned at the end of each line. When you copy to the line, you inherit that interpolated pscale value. You can use an attributedelete, placed before the CopyToPoints, to remove pscale and the spheres won't change size anymore.

Edited July 15, 2019 by Atom

[Valent]

@Atom But I need that pscale :), the spheres should be of different sizes, what's odd and what I was asking about is, if I try to change the attribute which drives carve_SOP it also changes pscale of these points 
If you have time, please look at the attached file. Try using a slider in the Null node named "CONTROLS".

[Atom]

I generally add pscale at the end of the loop. As long as pscale exists on the line, you'll have your problem.

ap_carve_q.hipnc

[Valent]

@Atom Thanks!

Could you please explain why it works this way

Looks like "carve" somehow messes with point numbers, I've remade it but instead of using @ptnum for pscale I used @primnum, and promoted it to points. And it worked.

carve_q2.hipnc

Edited July 16, 2019 by Valent

[anim]

carve will interpolate the attributes

so if one point has pscale of 1 and second 2, then if you carve in the middle the new point will have interpolated value in the middle of 1 and 2 so 1.5

then if you base your random on @primnum both points will have the same value so even interpolated value will be the same

[Valent]

@animThank you! You saved me from the sleepless night:)

Edited July 15, 2019 by Valent