Hi,
I’m still wondering how to convert a black’n’white image (done in illustrator or photoshop) into a mask to apply on a Plane3d and extract it?
Is the image able to map onto the model? In other words, was it created for the model’s UV’s? If so, use the Tool>Texture Map menu to apply it to the model. Then in the Tool>Masking menu you will find masking options such as By Intensity. This will use the texture to create a mask.
If the image is just an image, you will want to load it into SpotLight and then project it onto your model as PolyPaint. From there you can use the masking options like in the previous paragraph.
You could also use Shadowbox instead of extraction. See my post here on how to use images in Shadowbox.