Hi there! I am a beginner in TD and I am learning with video tutorials and I see very often the “null” operator. I must admit that I don’t understand what it is used for exactly. could you help me? Thanks in advance! 
Thanks for your question. The main use of the Null operators is that it acts as the endpoint for your chain of operations that can be consistent referenced elsewhere. It allows you to add extra nodes in the chain without needing to rewire references to the end of the chain.
For example if you had your Phong MAT referencing a Edge Detect TOP, but you wanted to add a Level TOP after that and change what the MAT is using, you’d need to add the Level TOP, and then make the Phong MAT reference the Level TOP instead.
If it’s already referencing a Null TOP, then you just put the Level TOP between the Edge Detect TOP and the Null TOP to add that operation to the chain, and the Phong MAT continues to work as you want.
3 Likes
thanks @malcolm! Your example is welcome to better understand the theoretical explanation! 