[Sidefx-houdini-list] two keyframed expressions on a single parameter

Andrew Lyons tstexture at gmail.com
Tue May 24 13:37:39 EDT 2011


Here's the thing. There are 2 ways to put an expression on a parm:

1./ Backtick contained expression
* no keyframe
* parm does not turn green
* you cannot toggle the display to see the expanded value though...

2./ Expression on keyframe
* Single keyframe with expression function attached. fit01() and sturb() are
just as valid as cubic() and bezier().
* Can have multiple keyframes with unique expressions per segment.
* you can toggle the display to see resolved value at any frame.
The confusion came about for many (myself included) post Houdini v9 when
there were some changes to the way parms were displayed, and with the
addition of automatic keyframing of expressions in the new UI code. I used
to only use the first approach, but these days Houdini will keyframe an
expression by default - perhaps because it's very desirable to see the
expanded value. You then however run the risk however of setting multiple
keys. It's also not simple to cut and paste an expression from one mode to
another because of the auto-insertion of backslash escapes around certain
characters in the second mode. It's kind of tricky. To use the first mode
these days you have to RMB and manually delete the channel from the parm to
preserve the original expression. I sometimes have two instances of a node
with the same expression in each node - one in each style so that I can edit
one, but see the expanded value in the other. I cut and paste the changes in
the first to the second as I go.  :\

Cheers



2011/5/24 Pablo Giménez <pablogipi at gmail.com>

> No Tom you are not crazy.
> Thsi has happened to me lot of times, a really annoying problem.
> I think would be nice to have an option in the preferences to avoid having
> keyframes and expressions in the same channel.
> Most of the times is an error.
>
>
> 2011/5/20 Tom Nixon <ignivomous at gmail.com>
>
> > Hey all,
> >
> > It seems at work as though I'm the only person who accidentally creates
> > multiple keyframed expressions in my parameters on different frames when
> > working with OTLs. This will usually be caught after wasting a day trying
> > to
> > figure out why something is breaking only to discover that there is a
> > keyframed expression on frame 17 that does not work any longer and the
> new
> > functional expression is at frame 0.
> >
> > My coworkers are probably starting to think I'm insane. Does anyone else
> > ever have this happen? Does anyone know what is causing this to happen
> (as
> > I
> > have not yet been able to reproduce this intentionally)?
> >
> > Thanks,
> > Tom
> > _______________________________________________
> > Sidefx-houdini-list mailing list
> > Sidefx-houdini-list at sidefx.com
> > https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list<https://lists.sidefx.com/mailman/listinfo/sidefx-houdini-list>
> >
>
>
>
> --
> Un saludo
> Best Regards
> Pablo Giménez
>  _______________________________________________
> Sidefx-houdini-list mailing list
> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list<https://lists.sidefx.com/mailman/listinfo/sidefx-houdini-list>
>



-- 
=======================================
Andrew D Lyons | Digital Artist | http://www.tstex.com
=======================================



More information about the Sidefx-houdini-list mailing list