attribute access in parameters

[saca]

hi,
i have simple wondering with attribute access for parameters input.
here is "dist" attribute from distanceAlongGeo(SOP).

on PolyWire(SOP)/radius, i can access with "@dist".
on Mountain(SOP)/height, i cannot access with "@dist".

by other way, point() expression,
on PolyWire(SOP)/radius, i can access point(opinputpath(".",0),$PT,"dist",0) too.
on Mountain(SOP)/height, i cannot access point(opinputpath(".",0),$PT,"dist",0) neither.

what reason these difference?
thanks.

falloff_distance_v001_002.hip

Edited April 8, 2022 by saca

[Librarian]

@saca attribute rename Mask(or dist) to "height" than you no need to have @ in parameter in Mountain SOP....

if you open(allow editing mountain  Sop you goona see inside VOP why ...you can use falloff node with Blend function also and rest
float blend = point(0, chs("../attrib"), @ptnum);
@P = lerp(@P, point(1, "P", @ptnum), blend);

Edited April 8, 2022 by Librarian

[saca]

thanks.
that's right in this case.
How can I tell the difference between the methods?

falloff_distance_v001_003.hip