[Bf-cycles] uv coordinates in Cycles standalone

Tue Dec 15 11:39:15 CET 2015

Guillaume,

Don't give up. I suggest building a pointcloud export and figuring out
the indexing out of primitive exports first. Perhaps export a single
quad as that was all I needed for my implementation, but I am sure you
can find out how the winding works in a triangle list. Wish I could
help you more...

Cheer up,
Jasper

On 15/12/2015, Jasper Kindt <jasper.kindt at gmail.com> wrote:
> Guillaume,
>
> Don't give up. I suggest building a pointcloud export and figuring out
> the indexing out of primitive exports first. Perhaps export a single
> quad as that was all I needed for my implementation, but I am sure you
> can find out how the winding works in a triangle list. Wish I could
> help you more...
>
> Cheer up,
> Jasper
>
> On 14/12/2015, Guillaume Rouault <guillaume.rouault.fx at gmail.com> wrote:
>> Hi again,
>>
>>  @Nathan, you mentionned to me somewhere that uvs a listed by triangles,
>> but in the example file you gave me:
>> https://github.com/jesterKing/CCSycles/blob/master/tests/objects/uv_cube.xml
>>
>> uvs are clearly listed by squares ( 6 of them of course)
>>
>> To be honest, I have really hard time exporting my uvs from houdini. I've
>> tried a lot of things already, and nothing seems to work, I am on the
>> verge
>> of giving up frankly, which would be a shame, because uvs are my last
>> main
>> issue, I have almost a basic working solution for simple animations
>> rendering with houdini.
>>
>> Guillaume
>>
>> On Thu, Dec 10, 2015 at 1:14 PM, Guillaume Rouault <
>> guillaume.rouault.fx at gmail.com> wrote:
>>
>>> After reflection, It's dumb of me to think that the error comes from
>>> source code. It definitely comes from my python code :
>>> I was able to render correctly the example object you gave me
>>> 'uv_cube.xml'
>>>
>>> Guillaume
>>>
>>> On Thu, Dec 10, 2015 at 12:45 PM, Guillaume Rouault <
>>> guillaume.rouault.fx at gmail.com> wrote:
>>>
>>>> Thank you guys for your answers, I wanted some infos, and I have plenty
>>>> of them now ^^ .
>>>> I am trying to code a exporter from Houdini to Cycles Standalone. I use
>>>> python to do that in houdini 15.
>>>> The fact is , I am really bad at C++ and after several hours of reading
>>>> the source code, my head hurts a little ^^ .
>>>>
>>>> indeed a lot of infos in cycles_xml.cpp
>>>> I adapted my export script to try and mimic the way mesh is computed.
>>>>
>>>>  in the part of the code you mentionned
>>>> https://developer.blender.org/diffusion/C/browse/master/src/app/cycles_xml.cpp;65ff373f0c71c043dd7b5632580501f1fc4bea7e$982
>>>>
>>>> Is it normal that the variable 'index_offset' stays at 0 ?
>>>> Shouldn't it be incremented at every iteration ?
>>>>
>>>> Guillaume
>>>>
>>>> On Thu, Dec 10, 2015 at 6:42 AM, Nathan Letwory <nathan at mcneel.com>
>>>> wrote:
>>>>
>>>>> -----BEGIN PGP SIGNED MESSAGE-----
>>>>> Hash: SHA256
>>>>>
>>>>> I haven't actually tested this in the C++ standalone version, but only
>>>>> in my C# CCSycles tester, but check out
>>>>>
>>>>> https://github.com/jesterKing/CCSycles/blob/master/tests/objects/uv_cube
>>>>> .xml
>>>>> <https://github.com/jesterKing/CCSycles/blob/master/tests/objects/uv_cube.xml>
>>>>>
>>>>> You'll have to add a texture coordinate input node and connect it to
>>>>> the image texture node (vector). That should have your shader use UV
>>>>> coordinates from the mesh data.
>>>>>
>>>>> UV coordinates are per triangle (you can double-check here:
>>>>> https://developer.blender.org/diffusion/C/browse/master/src/app/cycles_x
>>>>> ml.cpp;65ff373f0c71c043dd7b5632580501f1fc4bea7e$982)
>>>>>
>>>>> Here a custom RhinoCycles material using XML with a texture coordinate
>>>>> input node:
>>>>> https://github.com/mcneel/RhinoCycles/blob/master/Materials/BrickWithChe
>>>>> ckeredMortar.cs
>>>>>
>>>>> And here for the C#-way of creating nodes in RhinoCycles where I set
>>>>> projection and mappings
>>>>> https://github.com/mcneel/RhinoCycles/blob/master/RenderEngine.Utils.cs#
>>>>> L131
>>>>> <https://github.com/mcneel/RhinoCycles/blob/master/RenderEngine.Utils.cs#L131>
>>>>> - - in this function the last else block is probably the most
>>>>> interesting, since here I connect the UV output from texture
>>>>> coordinate input node :)
>>>>>
>>>>> Hope that helps,
>>>>>
>>>>> /Nathan
>>>>>
>>>>> On 09/12/2015 23:42, Guillaume Rouault wrote:
>>>>> >
>>>>> > I couldn't find a file named blender_mesh.cpp in the sources I
>>>>> > have. And I think it would mainly give me some infos on how to
>>>>> > format the mesh in the xml object file. but my main issue, I think,
>>>>> > is at the shader level in the scene xml file, using the standalone
>>>>> > XML API . How do I force the shader to use uv coordinates provided
>>>>> > on the mesh ?
>>>>> >
>>>>> > Now that I think of it, there are no examples using uv mapped
>>>>> > objects in the /examples folder, at least nothing using coordinates
>>>>> > generated during modeling.  Is it even supported at this stage in
>>>>> > the standalone version ?
>>>>> >
>>>>> > Guillaume
>>>>> >
>>>>> > On Wed, Dec 9, 2015 at 10:19 PM, Mohamed Sakr <3dsakr at gmail.com
>>>>> > <mailto:3dsakr at gmail.com>> wrote:
>>>>> >
>>>>> > in blender_mesh.cpp, find attr_create_uv_map() function and see
>>>>> > how they create UVs
>>>>> >
>>>>> > On Wed, Dec 9, 2015 at 10:26 PM, Guillaume Rouault
>>>>> > <guillaume.rouault.fx at gmail.com
>>>>> > <mailto:guillaume.rouault.fx at gmail.com>> wrote:
>>>>> >
>>>>> > Hi,
>>>>> >
>>>>> > I can't find any infos on uv coordinates for cycles standalone. As
>>>>> > of now, I haven't been able to render an object with the correct
>>>>> > uvs. I can see a texture, but it's mapped to every triangle on the
>>>>> > mesh.
>>>>> >
>>>>> > I searched the xml api , and came up with that setup :
>>>>> >
>>>>> >
>>>>> > *<!-- floor shader-->* *<shader name="floor" >* *<diffuse_bsdf
>>>>> > name="diffuse" roughness="0.05" color="1.0, 1.0, 1.0" />*
>>>>> > *<glossy_bsdf name="glossy" roughness="0.05" color="0.2, 0.2, 0.2"
>>>>> > />* * * *<texture_coordinate name="uv" />* *<image_texture
>>>>> > name="tex" src="./maps/aaa.jpg" />* *<add_closure name="mix" />*
>>>>> > *<fresnel name="fresnel" />* *<connect from="fresnel fac"
>>>>> > to="glossy color" />* * * *<connect from="uv uv" to="tex vector"
>>>>> > />* *<connect from="tex color" to="diffuse color" />* * * * *
>>>>> > *<connect from="diffuse bsdf" to="mix closure1" />* *<connect
>>>>> > from="glossy bsdf" to="mix closure2" />* *<connect from="mix
>>>>> > closure" to="output surface" />* *</shader>* * * * * Am I on the
>>>>> > right path ? * * Are there any examples or infos on uvs somewhere
>>>>> > ? Actually, on my meshes,  I don't even know if I have to export uv
>>>>> > coords as vector2  (uv) , or vector3 (uvw) ? * * * * *Guillaume*
>>>>>
>>>>>
>>>>> - --
>>>>> Nathan Letwory
>>>>> -----BEGIN PGP SIGNATURE-----
>>>>> Version: GnuPG v2
>>>>>
>>>>> iQEcBAEBCAAGBQJWaRDMAAoJEKtfN7KsE0TtOXsH/2soTeJzRwChnzexs2SqgnJc
>>>>> QWFo750pglTVpmmH2SDLGKg6fVofCYPzhc5UWnbR1+mlCkC+E8VsBLLu6CaG5Whb
>>>>> 6Tfwq7uOE9Rht1dlE2PxzhzaoV/Q++cOIgubaCfq3sofBXIE5qbjYSLwtyrKDj7c
>>>>> lhrPx/FwaapEHzEArjfWENbESVEHb7kJh9d39E3qeeCarflBDgJKVNxVC/SoVnsM
>>>>> GZIrUWeujIhLpcWt6XN0P68jwQdyUnX6Kx8k7aN3iG6Un7BfxaqlY+/+W5sUKQhG
>>>>> w7c349NeHj+gTJzbYTdY3f9zMLrVc2Iz7eVCmVy048aK2nMvG6+PunXcLBh6KVQ=
>>>>> =/YDa
>>>>> -----END PGP SIGNATURE-----
>>>>> _______________________________________________
>>>>> Bf-cycles mailing list
>>>>> Bf-cycles at blender.org
>>>>> http://lists.blender.org/mailman/listinfo/bf-cycles
>>>>>
>>>>
>>>>
>>>
>>
>