Hi All!
Recently I've been following this tutorial [www.pluralsight.com] about insects locomotion - I'm sure lots of you know this one- and unfortunately it was based in Houdini 11 environment So I have to research and make it work in Houdini 18, it's been quite a thrill ride. Here's the latest problem I encountered.
The input is a list of 240 points, with a attribute called “step”. The numbers in this attribute make sudden jumps like steps: first few points' “step” numbers are 1, and then a few are 2, and then 3, etc. See a screenshot of the spreadsheet below.
The tutorial guy then made a Group by Expression node, he wanted to find out the points that are about to jump in “step” attribute (for example, the point's “step” storing the last “2” before jumping to “3”). So he wrote this in the expression:
point(“../in”, $PT, “step”, 0) < point(“../in”, $PT-1, “step”, 0)
It selected the ones that about to jump, but ignored the points which has the same “step” attribute next to it.
I did some search on how expression changed in the past versions and did the following but couldn't make it work:
point(“../in”, “step”, @ptnum) < point(“../in”, “step”, @ptnum-1)
@step < @step-1 (this one will just select all points)
May I ask what would be the equiveloent in houdini 18?
Attached are few screenshots and the source file. The group by expression node is in the geo “prep_motion”