How to make a transparent 'shadow prim' in Maya?

[ivywren]

Like if I'm making a table and I want a transparent plane with the shadow on it.. How do I do that in Maya? Here's a pic of what I mean in case I suck at describing: http://gyazo.com/f043f5abf5df36698c8e8b8462b95018.png

Thanks!

[Chosen Few]

There are lots of methods, but here's a super easy one:

1.  Create your table, and light the scene as you see fit.  Make sure at least one light is set to emit ray-traced shadows.

2.  Place a plane underneath the table, with a pure white material on it.

3.  Bake a texture from the plane.  The texture will appear as a black shadow on a white background.

4.  Bring the texture into Photoshop, and invert the colors, so the shadow appears white, and the background black.  Use this as the alpha channel of a blank white image, save as 32-bit TGA, and upload to SL.

5.  Go back to Maya, export the plane, and upload it to SL.

6. In SL, apply the texture to the plane.  It will now look like a white shadow on an otherwise fully transparent surface.  Obviously, you don't want the shadow to remain white, so tint it whatever color you want it to be (black, gray, whatever).  You can also control the intensity of the shadow by adjusting its transparency setting in SL.  Enjoy.

As is the case with most written tutorials, this might seem like a lot of steps, when it's all written out like this.  But in practice, it's like 3 minutes worth of work. 

As I said in the beginning, there are lots of other ways to proceed, as well, but I like starting people with this one, because it is so quick and easy, plus it's universally applicable, not just for Maya, but for every other 3D modeling/rendering program.  If you were using Max, or Blender, or Lightwave, or what have you, the genral procedure would be the same.

 

Of course, another option is to stop using shadow planes, since SL has actual shadows now.

[ivywren]

I didn't even think about trying it that way. Thank you so much! :heart: