Meshes with an opacityTexture have no shadow: Problem or feature?

[JCPalmer]

The exporting of Blender procedural textures is essentially complete!  Gus the gingerbread man now looks straight from the oven, with his Noise procedure with diffuse & normal influence, and his Stucci Procedure normal influence.  FYI, a Blender texture can have "Influence" across multiple BJS textures.  The result was a material with 2 baked textures: diffuse using Noise, & bump using Noise & Stucci.

 

Now I started playing by adding alpha = .5 influence to the Noise Procedure, which caused a 3rd bake of an opacity texture.  Looked really interesting as you moved around it, but now there is no shadow, generated on the BJS side.  Is this supposed to happen?

[JCPalmer]

Related question, should baked textures ever need alpha in the file? The opacity texture seemed to be just 2 colors.  Here are the thumbnails:

The reason I ask is the exporter has to pick a file format, & whether the internal image has alpha.  I believe JPG is the best format from a file size perspective, but am pretty sure it does not handle alpha.  Is there a reason I should not hard code for JPG?

[Temechon]

Hey JC, 

 

Transparent material can't have shadows as it's not supported for the moment. 

You are right about jpg, they don't have an alpha channel as PNG or TGA have.

[JCPalmer]

Temechon, thanks.  I thought that was so about the shadows, but thought I would ask.

 

As far as hard coding JPEG as the output format.  It worked.  The opacity texture must not use alpha itself.  Did need to allow user to control the size of any baked textures & quality on a mesh by mesh basis.  Added 2 custom fields for meshes, as shown.  Found with JPEG, it was best to go with a large size 2048, but low quality like 50.  This matched the look of a 1024 PNG, but at a third less the file size.