[Sidefx-houdini-list] One dimensional noise() expression??
pablogipi at gmail.com
Mon Mar 8 10:17:57 EST 2010
2010/3/8 François Duchesneau <sidefx at trinix.ca>
> You can create your own expression like this and use it like that in a
> position y of a Point Sop.
> # New function noise1d
> vector nresult = noise(val, 1.1435, 993.782);
> return nresult;
> You could even create with that signature noise1d(val, freq, offset) to
> make things easier.
> I almost don't use Point Sop anymore, just to set normals to point or
> something like that. I prefer to do everything in Vop Sop and the
> Anti-Aliased Noise Vop allows you to do that out of the box and it's so
> much faster.
I also use vop sop almost for everything.
Thanks for the new expression function tip.
> Chris Mangnall wrote:
> > perlin noise is always zero at lattice points (ie. integers), so
> > noise($FF, rand($FF + 10), rand($FF + 56))
> > will always return 0 when $FF is an integer.
> > Try:
> > noise($FF * 0.1, 0, 0)
> > where 0.1 is the frequency.
> > Pablo Giménez wrote:
> >> Hi there.
> >> Well many times I have been thinking about what useful would be to have
> >> and tw odimensional noise() expressions.
> >> The current one needs three parameters, that is fine for a lot of
> >> but I really prefer to use a noise function ratehr than rand and having
> >> something like noise($F) would be good aI think.
> >> Maya noise function for instance allows this and is really handy.
> >> BTW I have tried to use expressions like:
> >> noise($FF, $FF + 10, $FF +56) and it always return 0, am I missing
> >> something?
> >> On the other side this works fine:
> >> noise($FF, rand($FF + 10), rand($FF + 56))
> >> But I think is to heavy, I mean we are calculating 3 pseudo-ransom
> >> in one call, too expensive.
> >> If I want to get a noise pattern but just from one value, what is the
> >> way? Adding offset to every parameter, multiplying, although this will
> >> affect frequency ...
> >> Ideas welcome :)
> >> Cheers
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