shadow mask bug

[bwcc]

I have a simple scene to illustrate the error - a few objects casting shadows on a floor object. when rendered normally it looks great.

 

I often render the shadow separately to build a composite in PhotoShop. I set all the the shadowing casting objects to "shadow object only" and the floor to "generate shadow mask" the alpha of that file will be the shadow.

 

when rendered, the alpha mask shows the shadow but also has a visible edge where the "outer cone" hits the floor object.

 

trying to upload the file but I get the error "Error This upload failed"

 

thanks,

brian

[Tomas Egger]

Ola Brian,

 

Please, send me in my email tom@eias3d.com

 

Thanks

 

Tom

[Tomas Egger]

Ola Brian,

 

I tested your project and sent you back, this only a problem of the light’s outer cone sizes and light’s references sizes.

Working as expected.

 

Thanks

 

Tom

[bwcc]

I can't believe this is the way it supposed to work - why would you want the outer cone visible in the shadow mask?

 

brian

[Tomas Egger]

Ola Brian,

 

Spot lights have a outer cone, it limit the shadows and become more clear here with RT. soft shadows activated.

Buffer Shadows and RT shadows without soft shadow doesnt have this problem, since you have a clean shadow of the object.

 

RT Shadows with soft shadows spread all the shadow in the surfaces, so, you dont have a clean difference between black and white, I attached another project here with default outer cone (45.0) and one light with Soft shadow angle of 10.0 instead of 60.0, take a look, do a render, the outer cone doesnt appear now, Why? when you use a value of 60.0, the shadow is all over the place making the black areas grey and appear limited by the outer cone, simple.

If you want to use 60.0 without a bigger outer code, you need only to go to AE or Photoshop and use Levels to crop the small grey values.

 

Now, you can believe this is the way it works.

 

Thanks

 

Tom

 

Project 9 sbTOM.zip