[Sidefx-houdini-list] Transfering normal to a volume

François Duchesneau sidefx at trinix.ca
Tue Nov 11 08:11:15 EST 2008


Thanks, the Volume Vop Sop method works

François

Andy Nicholas wrote:
> Doh! Yep, you're right, sorry it was the end of a very long day.
>
> In retrospect is what I meant to put is that you can get the closest point
> using nearpoint() and the $X $Y and $Z variables and get the normal from
> that, but my brain must have turned off halfway through ;-)
>
> A
>
>
>   
>> Unfortunately there are only X, Y, Z, V local variables.
>> It's possible to sample normals from points in VEX and bake them into i3d
>> (using i3d generator, works in any version of Houdini) or bake into Volume
>> primitive using Volume VOP SOP (H9.5 only).
>>
>> On Mon, Nov 10, 2008 at 11:28 PM, Andy Nicholas
>> <andy at andynicholas.com>wrote:
>>
>>     
>>> Hi François,
>>>
>>> I think you need to use the IsoSurface node with it set to "Build
>>> Volume".
>>> In the Implicit Function parameter just put $NX. Make two more
>>> IsoSurface
>>> nodes but with them set to $NY and $NZ. You can then just use a Merge
>>> SOP
>>> to merge them in X, Y, Z order, and extract them using the primitive
>>> number in your SHOP.
>>>
>>> Cheers
>>>
>>> Andy
>>>
>>>
>>>
>>>       
>>>> Hello,
>>>>
>>>> Is there a way to put normals to a volume. I want to generate a cloud
>>>>         
>>> pass
>>>       
>>>> with each bunch inside it being lit only on one side by a directional
>>>> light.
>>>>
>>>> I thought of a normal information per voxel so I can have my shader to
>>>> compute the the dot product with I but if there's an other way to it,
>>>>         
>>> I'm
>>>       
>>>> open to suggestion.
>>>>
>>>> One way I'm going to try is to have get the normal for the equivalent
>>>>         
>>> sdf
>>>       
>>>> surface but I still don't know how to transfer that attribute to each
>>>> voxel on the volume.
>>>>
>>>> Thanks
>>>>
>>>> François
>>>>
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>
>
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