VolumeData::trans vs VolumeData::alpha

[xNWP]

Hi all, I'm creating a MaterialData plugin type and need to set the alpha and transparency information. Could anyone verify the difference between Alpha and Transparency for me? From what I've gathered, transparency effects the objects opacity without effecting the rays in any way, whereas alpha will effect the ray intensity. Is this the only difference?

Thanks in advanced for any answers

[PluginStudent]

According to the documentation: transparency defines how much color the thing has: "A transparency texture is similar to a photographic slide: Red parts of the slide allow only red light to pass through; white parts allow all light through. With black, no light can pass through the slide."

Alpha defines if there is a thing at all: "An alpha channel enables you to use an image to mask out areas of the material, allowing any background to show through."

[r_gigante]

Hi @xNWP, thanks for reaching out us.

With regard to your question, has properly pointed out by @PluginStudent, transparency and alpha pertain to completely different aspects of a material definition. While the first relates to the color of a pixel for ray hitting an object with a transparent material the second relates to the overall contribution of that ray to the pixel. Finally the first usually is a 3-component vector and the second is a single-component float.

Cheers, R

[xNWP]

The distinction between pixel color and contribution of the ray to the pixel really helps clear things up. Thanks for all the help