[yt-users] Porting .ply files to Blender with colors?

[Matthew Turk]

Hi Jill,

On Mon, Feb 25, 2013 at 6:32 AM, Matthew Turk <matthewturk at gmail.com> wrote:
> On Mon, Feb 25, 2013 at 1:43 AM, Jill P. Naiman <jnaiman at ucolick.org> wrote:
>> Hi Matt,
>>
>> I've tried a few different things with PLY files and no luck.  Actually, I'm
>> not 100% sure if Blender really likes PLY files anyway - you can't even
>> export color easily in PLY format in Blender.  So, I've given up on PLY and
>> have hacked together a bit of a messy OBJ exporter:
>> http://paste.yt-project.org/show/3205/
>
> This looks nice.  We should incorporate this, or a modified version,
> into the AMRSurface object.  We used to have a .obj file format
> exporter, but I (incorrectly, it seems) thought the PLY format, which
> can be in binary and is thus much smaller, had feature parity.  Would
> you be up for making this a bit more general, and then adding it to
> the AMRSurface object?
>
>>
>> I'm probably doing the colors wrong, since there's likely a nicer way to get
>> actual "face" values then just taking the value at 1/3 of the vertex values,
>> but it worked, so I didn't mess with it too much.
>
> There is a simpler way, but honestly it's pretty non-intuitive and I
> think the face/vertex sampling in the AMRSurface is a bit clunky.  If
> you do:
>
> surf.get_data(field, "face")
>
> it will sample at the faces rather than the vertices.  This is also
> the default behavior for getting data through the dict-like method:
>
> surf[field]
>
> which should be face sampled.
>
>>
>> A few other things: (1) in theory, this can set transparencies, but I
>> haven't got that working as of yet, (2) the default specular (ambient?)
>> color settings make for a bit of a washed-out view in sketchfab:
>> http://skfb.ly/54jged0b, (3) the .mtl file is a bit too long since I'm
>> essentially setting each face as a different material, when one would just
>> like to use 1 material per color and set all the faces with that color on a
>> specific surface plot to that material, but I haven't got that bit working
>> well either.
>
> (2) Is this something that can be controlled by the materials editor
> on Sketchfab?

Quick followup -- by changing the "Rendering Options" to "Shadeless" I
was able to see things a bit better on Sketchfab.

-Matt

> (3) Ah, interesting.  One could do just 255 materials, for instance,
> and then that is now the colormap.
>
> This is definitely very interesting, and would be a huge upgrade for
> our Sketchfab / Blender / etc capabilities.  Thank you for sharing all
> of this!
>
> -Matt
>
>>
>> Thanks for the info, and please let me know if any of that doesn't make
>> sense.
>> -Jill
>>
>>
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