Create terrain mask using Redshift AO [UPDATED]

Learn how to create procedural terrain mask using redshift with fewer nodes.

Step 1:

Add AO node and select 'Return bent normals(object space)'.

when this mode is selected,AO node will return normals as colors.(RS State node connected to vector change range and setting 'old min range' to (-1,-1,-1) will also give similar output.)

Step 2:

Connect AO out with Color splitter and select 'Out G'.

Color splitter node can split colors into seperate channels.Out R gives red,Out G gives green,Out B gives blue and Out A gives alpha.Here we need Out G because from the AO normal we can see green color is facing upwards.

Step 3:

Connect Ramp node to Out G and set mapping to alt.

Ramp node is used to remap the outputs from the previous nodes.

Use ramp sliders to control the mask.

If you want to invert mask,right click on the slider and choose invert knots.

other way is to check invert normals in AO node or use Color invert node.In most cases invert Ramp knots is more preferable.

Step 4: 

Now use material blender and connect any two different material,then use our mask as layermask 1.

You can use one material for snow and another material for ground or viceversa.

Download project file and experiment yourself.
Thank you.