The question is in the subject. If it is, the formula to compute the trace of that process, as i know, is

dz=a*(dt)*(dt),

where dt is a time increment, dz is a value increment, a is a normally distributed random value, that belongs to N(0, 1).

If it is a Wiener process, what does parameters roughness & max octaves mean ? May i've misunderstood something …

No, aanoise is not a Wiener process. I should read the help more carefully

http://en.wikipedia.org/wiki/Fractional_Brownian_motion [en.wikipedia.org]

but … i still do not understand where is the ‘max octaves’ & ‘roughness’ parameters in that process …

please have a look here:

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=19224&start=0&postdays=0&postorder=asc&highlight=&sid=6fcdf0f16e8c306a17878deb7fbdd2bc [sidefx.com]