Hello there, I'm following Applied Houdini Rigid II.

Here's the part on cache of each voronoi pieces to disk, before cache, attached a delete node to select each piece based on their attribute “class”.

What puzzled me is in the tutorial, the group in delete node is ==> @class='$F', it seems malfunction in current H18.The attribute locked on @class=0 on whatever frame.
Could someone explain the difference between “$F” and $F, it seems really make no sense to use “$F” at first glance.

So I use ==> @class=$F instead, it turned out to be good, with one piece shown and others deleted, cool!
But!
Since $F start from 1, the @class start from 0, thers's one piece missing.
On consider of this I typed in ==> @class= ($F-1), the node stop working, in the geometry spread sheet, there're attribute on class=0 and class=1.

Plus, when I change it to ==> @class= ($F), it also not worked, but in the geometry spread sheet, there's only attribute on class=0.

How could I get the 0-99 pieces based on frame 1-100 without changing the attribute order?

it's probably not @class='$F', but @class=`$F`you need to use ticks `, not quotes ' to evaluate string as expression, however simple variables are expanded even without them therefore @class=$Fwill work

for more complex expressions you will need to use them though, so : @class=`$F-1`

tamte
it's probably not @class='$F', but @class=`$F`you need to use ticks `, not quotes ' to evaluate string as expression, however simple variables are expanded even without them therefore @class=$Fwill work

for more complex expressions you will need to use them though, so : @class=`$F-1`

!!!
That also explain the Error in my file cache directory expression, the string expression should always be in ticks``, not quoto''

Thank you very much !