group by expression

[FredDoes3D]

Hi there, 

I am currently following the quite amazing tutorial by Jonah Hall called Creating Procedural Rigs and Controlling Motion in Houdini
on Pluralsight. It has been released a few years back (2011 i think) so he is using an older version of houdini.

Most of it can easily be recreated in H16 but 2/3 into the tutorial he groups points using the group node and the "point" expression and i am having troubles recreating the same effect in H16, the way grouping works has changed quite a bit from what i can tell with my limited experience and I'm a bit stuck.

The expression he uses goes something like:

point("../in,$PT,"step",0) < point("../in,$PT-1,"step",0)

from what I understand he is comparing each point with its neighbor on the connected line ($PT-1) and groups based on the step attribute (step is created in chops based on earlier generated motion data)

Could any of you point me in the right direction of how to approach this? Thank you!

Frederik

[FredDoes3D]

Anybody?

Was hoping this would be an easy "this is how you do it in 2 easy steps..." for any veteran  

Best,
Frederik

[f1480187]

Try Group Expression node. I assume step is an integer attribute, otherwise use f@step and float(...) typecast function.

If the operator path (you have mismatched quotes, by the way) is an input node:

i@step < int(point(0, @ptnum-1, "step"))

If the operator path is a different node, so you really need to specify a path:

int(point("op:../in", @ptnum, "step")) < int(point("op:../in", @ptnum-1, "step"))

 

[FredDoes3D]

Cool! f1480187  thank you taking the time!
Will try it when I get home. 

Cheers

 

Edited August 23, 2017 by FredDoes3D