Shadows on Alpha-Mapped Materials

I have a plane with a blend texture mapped to the alpha of the material, making half the plane transparent and half solid (with a fade between the two areas). The problem is that the solid area receives shadows, while the transparent area does not.
I need all of the plane to receive shadows somehow.


example.blend (268 KB)

methinks you need to rethink. If the plane is transparent at the left edge there, it does not reflect light back to the viewer. Therefore, it cannot “show” you a shadow, since it does not reflect any light at all. Transparent stuff does not bounce green light or any light back to the camera.

It does not seems to work with Orco mapping, but if you add UV coordiantes to the plane and change the planes material to use those coordinates the shadow falls across the entire plane.

@PapaSmurf: I realise it’s not physically accurate, but it is for compositing over a real photo. What I’m trying to do is blend the CG plane into the real plane in the photo, meaning CG objects casting shadows on the CG plane also need to cast shadows on the real plane (to make it blend in nicely).

@Atom: I just tried your suggestion but it doesn’t seem to have any affect on the shadow.

Duplicate the ground plane with “shadows only” and “trans shadow” applied to a basic material.put the duplicate plane just under the textured plane.


example.blend (56.1 KB)

@pappy: Thanks for that, it seems to work fine :). The only problem I can see is that the shadow can’t be right on the original plane without causing intersection problems.