how to have render layer only to render shadow catcher?

Question

I have a building model with complete material and uv setup. Everything is fine, but now i want to render separate shadow layer. HOw can i have seperate layer which only turn on shadow catcher ? when i turn shadow catcher it will apply globally. Is it possible to have 2 render layer in sama scene where first layer render all object while the second layer render only shadow ? THe only thing i can do here, is to duplicate the project into another file just to render the shadow.

Thanks

Answer 1

First, create two separate render layers.

Second, duplicate all your objects to the second render layer. Then on the first layer in all your lamp settings turn off "Cast Shadow".

On the second layer, turn all your objects into shadow catchers.

Once your done, hit F12 and Blender will render both your images!

Answer 2

My answer is not the full explanation, but gives good directions,check that your film is transparent. In node select composite and ad a viewer output, wire it to a render layers node. add two render layer node´s. then go to layers, and add so that when the other layer is on the other is masked and. and when layer 1 is on is layer 2 excludet. Then select in the render layer the box, layer only selected layer .. and check the layer that you want to render. This way you should be ably to render the layers in the same scene ...but if you put shadow catcher on i think it will make all layers to make the shadow catcher. you have to have it off to render normal objects. i my self managed to have the shadow catcher and object in layers with out making a separate file, so i would say you don´t need to do that.

Answer 3

My suggestion would be to set the objects that you don't want to appear in the shadow layer as a holdout. This would only be possible in Blender 2.8 and above and would make a transparent cut-out in the shadow where that geometry occludes the shadow.

1. Create a view for the Shadow.
2. Place the geometry in its own collection and the shadow catcher in its own collection.
3. Right click on the geometry collection and select Visibility > Set Holdout. This will set the holdout only on the Shadow Catcher's view layer.