Wow, I shouldn't have wrote that late last night, I completely
mixed things up in my previous post, sorry!
I'll try again! With a ramp, you have the source (input) values
on the X axis, and the target (output) values on the Y axis. If
either your source or target values aren't in the range [0, 1],
you can remap them using a simple float parameter (to use as a
simple multiplier if your desired lower bound is 0), or a float2
parameter to precisely control the desired range.
It seems to be a standard practice in Houdini since they use it
for some built-in nodes, such as the Pyro SHOP.
Andy, the O(N) thing got me thinking and realized that instead of
running the attrib wrangle in detail mode, which uses only a
single thread, it'd be possible to generate say 4 points and, in
a point wrangle, let each of these points process 1/4th of the
array, thus effectively running the same logic on 4 threads!
Another attrib wrangle is then needed in post to sum up the
result from each point. Well, in all honesty I don't think
there'll ever be a use case for it :)
On 7 March 2017 at 01:14, Olivier Jeannel <facialdel...@gmail.com
<mailto:facialdel...@gmail.com>> wrote:
Ok we agree.
On Monday, March 6, 2017, Jonathan Moore
<jonathan.moo...@gmail.com
<mailto:jonathan.moo...@gmail.com>> wrote:
As far as I understood it Oliver, the spline version of
the Houdini Ramp only operates in the zero to one range.
You re-fit the values pre/post/ or both to suite your needs.
I get that this doesn’t match the UX of FCurves in XSI,
but I’ve always understood Ramp’s in Houdini to be more
of a lower level discrete element in visual programing terms.
*From:*softimage-boun...@listproc.autodesk.com
[mailto:softimage-boun...@listproc.autodesk.com] *On
Behalf Of *Olivier Jeannel
*Sent:* 06 March 2017 17:31
*To:* Official Softimage Users Mailing List.
https://groups.google.com/forum/#!forum/xsi_list
<https://groups.google.com/forum/#%21forum/xsi_list>
<softimage@listproc.autodesk.com>
*Subject:* Re: houdini question (and where to ask)
Not sure I get it Christopher (not in front of H)
Does your trick actualy change the graph visualy ?
In short, can I see the negative x & y values ?
On Monday, March 6, 2017, Christopher Crouzet
<christopher.crou...@gmail.com> wrote:
Indeed, which is why I mentioned the “detail” mode
which brings you back to O(N). Not saying that one
approach is better than the other though, only that
it is possible.
On 7 March 2017 at 00:12, Andy Nicholas
<a...@andynicholas.com> wrote:
Yep it is possible, but you wouldn't want to do
it because each calculation of the maximum value
would be running across N points to calculate
that. That'd make it an O(N^2) operation, albeit
spread over multiple threads.
It might seem like a pain to have to do this in
advance using an Attribute Promote, but by doing
so, it's actually forcing you to work in a more
efficient way. Go with it ;)
On 06/03/2017 16:32, Christopher Crouzet wrote:
It /is/ possible to retrieve the maximum
value in a VOP since nothing stops anyone
from manually iterating through all the
points of the geometry. This kind of
operation might be more suited in “detail”
mode though.
Also, having the ramp normalized to the [0,
1] range in both the X and Y axis is usually
“workarounded” by adding a float parameter
for the amplitude (Y axis) that is used as a
global multiplier (making later tweakings
convenient!), and a float2 parameter for the
target range (X axis) that is then remapped
using `fit("my_ramp", 0.0, 1.0, range_min,
range_max)` (which is also convenient for
later tweakings!).
Now, if you really want to have an actual
FCurve, then just create a simple float
parameter, add all the keys however you want,
then query it in using `chf("my_param",
the_time_in_seconds)` in VEX/VOP, or using
the equivalent expression.
On 6 March 2017 at 23:29, Jonathan Moore
<jonathan.moo...@gmail.com> wrote:
Fabricio ,
The Attribute Promote help page has
approx 15 examples you can load.
Hopefully you might find something within
the examples to inspires a solution.
*From:*softimage-boun...@listproc.autodesk.com
[mailto:softimage-boun...@listproc.autodesk.com]
*On Behalf Of *Olivier Jeannel
*Sent:* 06 March 2017 15:56
*To:* Official Softimage Users Mailing
List.
https://groups.google.com/forum/#!forum/xsi_list
<https://groups.google.com/forum/#%21forum/xsi_list>
<softimage@listproc.autodesk.com>
*Subject:* Re: houdini question (and
where to ask)
You can't get the "get maximum in set"
when inside a vop.
But, you get those options with the
promote attribute sop.
On Monday, March 6, 2017, Oscar Juarez
<tridi.animei...@gmail.com> wrote:
I would like to be proven wrong, but
that would be the way, I mean in your
second pointvop you don't need to add
another noise, your noise is already
saved in an attribute, when you
promote just check off delete
original and you can access the same
noise. Also noises have specific
output ranges, they come in the
documentation, so you can always add
a fit node to change your range to
what you need, in the geometry
spreadsheet you can also sort by
value so you can see max and min.
If you press X with your mouse over
the noise output it will add a
visualization node, you can visualize
on the viewport or in the geometry
spreadsheet the values. I know its
not the same but as far as I know
their is no way to do the same as the
get maximum in set node in a vopsop
context.
On Mon, Mar 6, 2017 at 3:57 PM,
Fabricio Chamon <xsiml...@gmail.com>
wrote:
thanks everyone. The ramp
parameter kind of works but as
you say, is not that user
friendly and does not show the
points below 0. (that's ok, but I
wonder if it is possible to write
a custom widget in houdini)
anyway, the thing I could not get
right just yet is that sort of
"get maximum in set" thing. Sorry
for using ICE language, I'm
trying to be open minded here, so
please tell me if that`s not the
correct mindset.
so on this graph:
Imagem inline 1
...how could I get the maximum
value of the output noise node
and compare to a single point
output of the same node?
From what I can tell, I'd have to:
1- create this pointvop node with
a turbnoise, then store the
output noise into an attribute
(via bindexport?)
2- up one level -> drop an attrib
promote (detail), set to maximum
3- drop another pointvop node
with another noise node inside
(same parameters) and compare the
result noise to that found on the
atrib promote node??
I'm 99% sure this is totally
wrong...how would you go about
that single task specifically?
and finally, thanks for the
suggestions on houdini forums and
discord. will try both (although
I pretty much like this list =) )
2017-03-06 15:17 GMT+01:00 gareth
bell <garethb...@outlook.com>:
yeah - the lack of handles is
frustrating
------------------------------------------------------------------------
*From:*softimage-boun...@listproc.autodesk.com<softimage-boun...@listproc.autodesk.com>
on behalf of Olivier Jeannel
<facialdel...@gmail.com>
*Sent:* 06 March 2017 14:05:17
*To:* Official Softimage
Users Mailing List.
https://groups.google.com/forum/#!forum/xsi_list
<https://groups.google.com/forum/#%21forum/xsi_list>
*Subject:* Re: houdini
question (and where to ask)
yep but it has no handles
and try to make négative
values, it takes them but
wont show on the curve as it
has a 0,1 space.
Unless i'm wrong (which i'd
love to be)
Le 6 mars 2017 14:36,
"Olivier Jeannel"
<facialdel...@gmail.com> a
écrit :
in vop, bind and bind
export node will get an
set datas.
Ramp Parameters is sort
of fcurve.
It's a bit weak in terms
of curve manipulation,
but does the job.
It has 2 modes rgb (ramp)
and spline.
If you use several ramps
in the same vop, name
them with different name
or they might not export.
Le 6 mars 2017 14:28,
"Fabricio Chamon"
<xsiml...@gmail.com> a
écrit :
..sorry, hit send too
soon.
Question #1: are
there any equivalents
to ICE "get ... in
set"? or or do I have
to iterate and store
values for later
comparision? In other
words: what is the
best or recommended
workflow to compare
single point data
with global point data?
Question #2: any
nodes that resemble a
fCurve node, like we
have in ICE? if not,
what is the alternative?
and finally, I can
see this list is
becoming more and
more houdini-esque
than ever..but, what
is the best place to
ask beginner
questions like the
above? houdini
foruns, houdini list,
odForce...
thanks!
2017-03-06 14:23
GMT+01:00 Fabricio
Chamon
<xsiml...@gmail.com>:
Hi, I'm slowly
getting into
houdini and this
is my first
attempt to port a
really simple
ridged fractal
deformer made in
ICE to houdini
(using pointvop).
Question #1: are
there any
equivalents to
ICE "get ... in
set"? or or do I
have to iterate
and store values
for later
comparision? In
other words: what
is the best or
recommended
workflow to
compare single
point data with
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