On 10/28/2016 1:03 PM, clipka wrote:
> Am 28.10.2016 um 11:35 schrieb Stephen:
>
>>> So this probably doesn't qualify as whatever Mike had in mind when
>>> suggesting that "POV-Ray should support point clouds".
>>
>> Are you sure we are talking about the same thing?
>
> Pretty much so.
>
>> It seems to me that df3's are point clouds.
>
> Nope. DF3 is a voxel format, which is an entirely different beast.
>
> You can think of a point cloud as just the bare vertices of a mesh, with
> no triangles to connect them up. Each point is explicitly specified by
> its set of coordinates, and the points are the primary data (although
> additional attributes may be associated to them, such as colours). Point
> clouds are often used to represent an object's volume by providing
> sample points on that object's surface (though there are also measuring
> processes that generate data points all across a given volume), and this
> type of point cloud data is often the raw output format of
> professional-grade 3D scanning devices.
>
> Voxel data, on the other hand, is the 3D equivalent of a pixel image: An
> implicit regular grid of "volume pixels" (hence the term) covering a
> (typically box-shaped) region in 3D space, and explicit attributes
> associated with each and every voxel, with the attribute values
> constituting the primary data. That data may represent pretty much
> anything: Colour, pressure, heat, wind speed and direction, or whatever.
> Representing an object's shape is just one possible application, in
> which case each voxel's data will represent what portion of each voxel
> falls inside the object's volume. Voxel data is almost always derived
> from other input data (such as point clouds).
>

If I understand what you said. Voxel data can be or is a subset of point 
cloud data.

So what is the problem with redefining coordinates in a df3 to points or 
small spheres instead of a cubical volume?

To all intents and purposes the df3s I have made in PovRay. Act like 
point clouds when using emitting media.


-- 

Regards
     Stephen

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