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

Andy Nicholas andy at andynicholas.com
Tue Nov 11 06:57:58 EST 2008


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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