[Sidefx-houdini-list] rotating noise

Ivan DeWolf ivan at martian-labs.com
Sun Nov 25 22:40:10 EST 2007



you can also rotate the geo with a xform SOP, and then feed the rotated geo into
the second input on your point SOP, and base your noise on $TX2,$TY2,$TZ2...

Quoting Calin Casian <calin at sidefx.com>:

> I may not understood what you wan to do but can't you use vex to play with
> the noise. attach a rest attribute to your geo so that the noise stick to
> the surface and then do whatever you want in vops. Again I might
> misunderstood you.
> 
> 
> 
> 
> 
> 
> > Yeah.. you can do the rotation in maths in the sops but it's harder and
> > more limiting than just rotating the source object around... then
> > rotating it back afterwards.
> >
> > Once you've set up your xform sops on either side of your noise sop you
> > can also scale/shear/translate the noise easily!
> >
> > Tip..
> > * make your initial transform sop
> > * RMB-Reference copy it
> > * tick the Invert Transformation at the bottom of the referenced copied
> > sop.
> >
> > This is faster an more flexible than putting -ch() expressions in.. and
> > you don't need to worry about reversing the scale/rotate/translate or
> > rotate x/y/z orders if you start doing more elaborate transformations.
> > It gets it right for you.
> >
> > Cheers,
> > r.
> >
> >
> >
> > Alvin Yap wrote:
> >> Can you not rotate the geo, apply the noise, then do a relative
> >> reference to the sop that did the rotation to get the inverse rotation
> >> hence getting the geometry back to the original position with the noise
> >> applied? I use that quite abit to scale groups of objects (shift geo to
> >> origin, scale, shift geo back to original location).
> >>
> >> HTHs!
> >>
> >> Alvin
> >>
> >> Adrian Lee wrote:
> >>
> >>> Thats the effect I want but is there anyway to do it with out rotating
> >>> the
> >>> geometry?
> >>>
> >>> On 25/11/2007, Louis Dunlevy <ld at dneg.com> wrote:
> >>>
> >>>
> >>>> If you're displacing then try rotating the normal instead. So if your
> >>>> current expression is something like:
> >>>> $TY + noise(blah)
> >>>>
> >>>> try:
> >>>> $TX+$NX2*noise(blah)   $TY+$NY2*noise(blah)   $TZ+$NZ2*noise(blah)
> >>>>
> >>>> you can rotate your geometry and stick it into the second input of the
> >>>> point sop which picks it up via $NX2 etc..
> >>>> or do it in vops.. ;-)
> >>>>
> >>>>
> >>>> Adrian Lee wrote:
> >>>>
> >>>>
> >>>>> Hello boys and girls,
> >>>>>
> >>>>> I have a noise expression in the $TX slot in a point node that nicley
> >>>>> displaces some geometry in the YZ plane. How can I then rotate the
> >>>>> noise
> >>>>>
> >>>>>
> >>>> in
> >>>>
> >>>>
> >>>>> X so the same noise is now applied at a slight angle? Thanks
> >>>>>
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> >
> 
> 
> -- 
> C A L I N   C A S I A N
> Production Specialist
> 
> Side Effects Software Inc.
> e-mail: calin at sidefx.com
> tel: (416) 5049876
> 
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> 


-Ivan

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"Perfection is achieved when nothing else can be removed"
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