Mask
Gaea 2 introduces the new Mask node which allows you to mask the node/effect after it has been created. You can connect the Mask node after an effect has been applied. For example, in a Mountain > Erosion > Mask scenario, the Mask will automatically use the applied mask between Mountain and Erosion.
If you're looking for 2D drawing node from Gaea 1, see Draw
If you have multiple nodes that create the "effect" you wish to mask, just connect the second port of the Mask node to the desired "before" node. For example, in Mountain > Erosion > Sandstone > Thermal2 > Mask, you would connect the second input to Mountain.
Properties
This is very useful because when a node is masked directly, a change to the mask will force a rebuild of the entire node. However, a Mask node adds masking as a post-process and is extremely fast.
There is no difference in results between the Mask port on a node and the Mask node. It is highly recommended that Mask node be used when possible as it will make your builds faster, and adapt your workflow to the modern specifications recommended by Gaea 2.0.
using AngryMonkey 