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[modo] Vertex Alpha

Revel
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Revel interpolator
Hi guys, I've been looking for a way to paint and view a vertex alpha map on modo but couldn't find any answer so far. Thought some of you guys here can point me to a right direction?

Purpose is to be able to blend 2 textures together based on a vertex alpha value to be used on Cryengine. Thanks~
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  • Farfarer
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    Farfarer
    There's no way to view the alpha :/

    The best you'll get is to use the math tool to city out of the map to a weight map or something, edit it, then copy it back in to the alpha.
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  • repete
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    repete polycounter lvl 6
    I "think" I am getting somewhere with the vertex colours. You can see them in the Setup view port but no where else.

    you still need to create an RGBA map under Weight Maps to paint your vertex map via the vertex map color tool. I guess you need to create a new RGBA map for each texture and I have no idea if this will get exported with FBX.

    I think this could probably be sorted using nodes as Farfarer suggests.

    In the pic you can see the RGBA map influencing the texture.



    aclue_zps9c18137d.png
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  • Owers
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    Owers polycounter lvl 10
    One of the small things that disappointed me about Modo 801 was the lack of vertex colour improvements. Eight releases now and you still can't easily manipulate vertex alpha despite meshes supporting it. The math tool is no good either because from my experience you can only transfer weight map values to the red channel, even when you choose 'component' and set the index value to 3. I can only assume it's a glitch.

    It is possible to view vertex alpha in Modo, and repete is on the right track. I'm still using Modo 701 for this example. Make sure you're in Advanced OpenGL mode first (can't view it in shaded/textured etc). Add a texture to your material (like a UV grid). Open your viewport settings (hold O), click the 'Active Meshes' tab and choose 'Selected' in the Vertex Map drop-down menu, then tick 'Show Weightmaps'. Create an RGBA vertex map and set your RGBA values (alpha can only be set using the Vertex Value command found in the Vertex Map menu above). Select your RGBA map in the Lists tab and you should see your texture where your alpha value is less than 1.0. That's your vertex alpha.

    modo_alpha.png
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  • repete
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    repete polycounter lvl 6
    You have clearly shown that it can be done :poly121:
    Owers wrote: »
    One of the small things that disappointed me about Modo 801 was the lack of vertex colour improvements. Eight releases now and you still can't easily manipulate vertex alpha despite meshes supporting it. The math tool is no good either because from my experience you can only transfer weight map values to the red channel, even when you choose 'component' and set the index value to 3. I can only assume it's a glitch.

    It is possible to view vertex alpha in Modo, and repete is on the right track. I'm still using Modo 701 for this example. Make sure you're in Advanced OpenGL mode first (can't view it in shaded/textured etc). Add a texture to your material (like a UV grid). Open your viewport settings (hold O), click the 'Active Meshes' tab and choose 'Selected' in the Vertex Map drop-down menu, then tick 'Show Weightmaps'. Create an RGBA vertex map and set your RGBA values (alpha can only be set using the Vertex Value command found in the Vertex Map menu above). Select your RGBA map in the Lists tab and you should see your texture where your alpha value is less than 1.0. That's your vertex alpha.

    modo_alpha.png
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  • Revel
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    Revel interpolator
    Hey this is interesting! I'm not sure I quite get it 100% cus I'm still fairly new with modo in general.

    When using Vertex Map >> Color Tool I can only click each vertex to make it 0% alpha, whenever i airbrushed it across the mesh it painted on the mesh (instead of just affecting alpha), where can I set which map to affect either RGB or A on an RGBA map? Also on Color Tool, the Alpha input always stay on 100% no matter I manually type 0% on the input field, whenever I airbrushed it, it straight snap to 100% alpha. Is this the expected behavior?

    I tried to import the FBX file to max, but it appears the vertex alpha is not exported together with the FBX exporter, can anyone confirm this? Or I might do something wrong on modo, I also welcome if anyone can upload a test FBX object from modo with edited vertex alpha so I can check it out over here?

    Thanks~!
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  • Owers
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    Owers polycounter lvl 10
    Revel wrote: »
    Hey this is interesting! I'm not sure I quite get it 100% cus I'm still fairly new with modo in general.

    When using Vertex Map >> Color Tool I can only click each vertex to make it 0% alpha, whenever i airbrushed it across the mesh it painted on the mesh (instead of just affecting alpha), where can I set which map to affect either RGB or A on an RGBA map? Also on Color Tool, the Alpha input always stay on 100% no matter I manually type 0% on the input field, whenever I airbrushed it, it straight snap to 100% alpha. Is this the expected behavior?

    I tried to import the FBX file to max, but it appears the vertex alpha is not exported together with the FBX exporter, can anyone confirm this? Or I might do something wrong on modo, I also welcome if anyone can upload a test FBX object from modo with edited vertex alpha so I can check it out over here?

    Thanks~!

    I've included two FBX files exported from Modo 701. One in FBX 2010 format and the other FBX 2013 format:
    https://dl.dropboxusercontent.com/u/52401794/sphereAlpha_2010.fbx
    https://dl.dropboxusercontent.com/u/52401794/sphereAlpha_2013.fbx

    It is possible to export vertex alpha values in Modo, however you must use FBX 2010 as your format. FBX 2013 doesn't seem to support vertex alpha despite being a newer format, which is hilarious and frustrating at the same time. FBX 2013 was introduced piece by piece in Modo 701, so maybe it's more complete and fixed in Modo 801 (but I don't know for sure, I haven't tried).
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  • Owers
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    Owers polycounter lvl 10
    Sorry for the bump, but I can confirm that FBX 2013 does indeed support vertex alpha in Modo 801. Which is very fortunate because they've ditched the original FBX 2010 format entirely.
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  • Revel
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    Revel interpolator
    I still not able to get it working, it all comes out as white. Is there any specific setting that you use?

    Also where did you confirm it? Did you bring to game engine like Cryengine for example?
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  • raul
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    raul polycounter lvl 11
    Hey guys, i put together a quick tutorial on how to do this. Now what im looking for is a way to be able to use those vertex colors to blend the textures inside of modo. So i can get a better idea at what im doing. I know i can do it through weight maps, but i really want to be abel to use the vertex colors instead. http://raparicio.com/wp-content/uploads/2014/11/Modo_VertexColors.jpg
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