Artifacts on AlphaTest Effect

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JoeGrouch Posted: 02-08-2011 6:03 PM

I've run into a strange occurrence on a billboard I'm using on a 3D model with the texture alpha.  I wanted to post to see if anyone had any ideas.

Note the black outlines apparent on certain portions of the transparent alpha.  Additionally, the card appears to have a black outline on the unclipped regions.  This should not be present either (and is also occurring in all the other cards using alpha blend).  I should also note that the alpha test effect is enabled on the model properties.  Any thoughts?

 

Regards,

Joseph G.

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Hey Joe,

Did you try adjusting the clipping amount? The higher the number the more pixels that are clipped from the transparency.

Let me know if it helps,

Alex

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I forgot to mention that this is registered with the object manager as a static model.  So this is the result of the alpha test setting for the model.  I'm not sure if I have any control over the alpha blend factor.  I'm guessing that this is a result of the anti-aliasing used in the textures.

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also, check to see if ALL your textures are power of two (16x16, 32x32...256x256....2048x2048...)

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Hi Joe,

I wanted to check in and make sure you were able to find and adjust the Transparency amount in the SunBurn editor.

As Alex mentioned this will allow you to adjust the amount of border visible at the edge of alpha-clipped materials.

Let me know if this helps!

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I did see that option, thank you.  That wasn't the problem once the model was imported via the Editor.  However, if the model is imported as a static model and the processor set to AlphaTest, the materials are not selectable in the editor, and therefore cannot have their properties adjusted.  I'm not sure if this is a bug or if I was simply using the processor incorrectly for a static object, but there was no way to adjust the clipping for the static model.  Nevertheless, it's not a problem now.  Thanks again.

Regards,

Joseph

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SunBurn_Studio_Licensee

Hi Joe,

Ahh, ok I see what's happening now.  When you load the model through the editor it's processed using the SunBurn model processor, which applies SunBurn's materials to the model.  This adds all of the built-in material effects and also alpha-clipping.

It sounds like your project is manually loading the model using XNA's default model processor, which SunBurn does support, but has fewer features and is not editable via the editor.

If instead you set the model's processor to the SunBurn processor, it will load (still manually so you can interact with it in code) containing SunBurn materials, which you can modify in the editor (including setting the transparency amount).

Let me know if this helps!

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