[Sidefx-houdini-list] One dimensional noise() expression??

François Duchesneau sidefx at trinix.ca
Mon Mar 8 09:03:10 EST 2010

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[1];

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.


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 one
>> and tw odimensional noise() expressions.
>> The current one needs three parameters, that is fine for a lot of situations
>> 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 numbers
>> in one call, too expensive.
>> If I want to get a noise pattern but just from one value, what is the best
>> way? Adding offset to every parameter, multiplying, although this will
>> affect frequency ...
>> Ideas welcome :)
>> Cheers
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