[Sidefx-houdini-list] sweep

Jeff Wagner jeff at sidefx.com
Tue Oct 11 11:30:22 EDT 2011


Look at the help for the Sweep SOP. There are some nice local variables 
that allow you to process multiple curves easily.

$PT returns the current vertex point along each backbone from 0 to n-$NPT
$NPT returns the total number of points in each backbone curve.
$PATH returns the primitive number if you want for example a random seed 
for each backbone curve.
$PCT is the percentage along the backbone for each curve.


So in scale you could add a slight bit of randomness for each profile by:

$PCT + if($PCT==0, 0, rand($PT + $PATH))*0.1

with the if() statement to make sure that you add no random scale value 
at the start of the curves.

To make cubic tapered ends, you can gang two smooth() functions together 
like this:

(smooth($PCT, 0, 0.1) - smooth($PCT, 0.7, 1)) * 0.5



-jeff

On 11-10-07 3:39 PM, zoran arizanovic wrote:
> thanks larry
> :)
>
> On Fri, Oct 7, 2011 at 9:29 PM, Larry Giunta<larry at gcreativestudios.com>wrote:
>
>> Hey Zoran,
>>
>> If I understand correctly, I've done something like this before by adding
>> an expression in the scale parameter on the Sweep SOP.
>>
>> In my case I needed it to be consistent for most of the curve, then scale
>> to a zero at the end. So I enclosed it in a clamp function.
>> Something like this.
>> clamp(($PT*.1), 0, 1.5)
>>
>> Larry
>>
>> --
>> Larry Giunta
>> Creative Director
>> G Creative Studios
>> (978)276-0600
>> www.gcreativestudios.com
>>
>>
>>
>> On Oct 7, 2011, at 3:03 PM, zoran arizanovic wrote:
>>
>>> hi
>>> I would like to control thickness-diameter of crosssection circle
>>> I have a circlethrough sweep sop  along dynamic curves and would like to
>>> control it so  it goes gradually to zero on the top of a curve
>>> so the sweeped geo would be the thickest at point0 and  zero scale at
>> point
>>> X-end point
>>> thanks
>>>
>>>
>>> --
>>> Zoran Arizanovic
>>> vfx reel : http://vimeo.com/28605448
>>> http://www.imdb.com/name/nm2902303/
>>> _______________________________________________
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>>> Sidefx-houdini-list at sidefx.com
>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
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>
>




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