[Sidefx-houdini-list] Will Ramps premote from a vopSop to an obj to a subnet happly

François Duchesneau sidefx at trinix.ca
Tue Apr 13 07:36:07 EDT 2010


Correct me if I'm wrong but the method you're talking about cannot be 
used in a vop meant for shading and it might not be as fast as a ramp 
vop. That brings me to say that we need more control on the ramps, i.e. 
bezier or other flexible type of interpolation and the ability to expand 
the window the ramp widget for more precision in the placement of points.

François

Rangi Sutton wrote:
> Hey Rob,
>
> I think I understand what your asking.. might not.
>
> Anyway, my approach.. you create your vopsop with a ramp parameter, 
> inside as asset. You promote the ramp by dragging the label of the ramp 
> from the vopsop's parameters onto the "Existing Parameters" column of 
> the assets Edit Operator Type Properties window. Apply this.
>
> That should be a live ramp link kinda deal.. you can add points and 
> stuff on the top level.
>
> I haven't a clue how to apply that link to another vop. I manage it by 
> taking the vopnet that the ramp was promoted from, and copy and paste 
> that node. The new node is linked to the param. Oooh.. dirty... but gets 
> you there. Should work for what you describe below.
>
> But you know what.. ramps are kinda nice and kinda not nice. Louis 
> recently showed me a trick to manage chf() style lookups inside of vops. 
> So you use the channel editor to describe your float-ramps rather than 
> the fidgety ramp editor.
>
> You create an inline code vop, with "$out = ch( $channelPath, $lookup 
> );" as the code. Config the IO so you've got an input "lookup" float and 
> an input "channelPath" string, output is a "out" float. Now that's just 
> using a single channel to store the ramp, as per the old skool, which is 
> rool easy to promote.
>
> I'll email you an asset offlist demo-ing the channel-y referency goodness.
>
> Beers,
> r.
>
>
>
> Robert Kelly wrote:
>   
>> Hi Peeps
>>
>> I am integrating a VopSop with a ramp and promoting it once to an
>> asset at object level then inside another Subnet asset that gets
>> interacted with, it has 12 of the object assets.  so....
>>
>> + main subnet asset (locked)
>>     + obj asset 1 (same type of asset for the siblings)
>>          + vop_sop_with_ramp
>>     + obj asset 2 (same type of asset for the siblings)
>>          + vop_sop_with_ramp
>>     + obj asset 3 (same type of asset for the siblings)
>>          + vop_sop_with_ramp
>>     + obj asset 4 (same type of asset for the siblings)
>>          + vop_sop_with_ramp
>>     + obj asset ...... up to 12
>>
>> so can i promote a ramp parm from the vop sop to the object level then
>> have all of the obj assets read one ramp?
>>
>> It always seams to turn the reference of a ramp into a bunch of ch()
>> references that are specifically keyed into the one time you promote
>> the value. Many child ramps referring to one parent ramp isn't a
>> smooth operation.
>>
>> I could use a point sop and a chramp() expression but this makes a 130
>> ms operation into a 2300 ms operation and that times 12 is a big hit.
>> My plan B is to sample the ramp into 100 points of geometry and use
>> that geometry as a representation on the ramp.
>>
>> if you have any ideas on a better way or something i am missing let me know.
>>
>>   
>>     
>
>   



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