compairing normals in vex

[meshsmooth]

This is my first post so a little introduction is in order.

My name is Robert Kelly I have been doing 3d for the last 6 years and working in 3d for the last 4, mostly in max but also in animation master AKA "Hash". In max I have always modelled in a procedural fashion and about 4 years ago I herd of this mysterious 3d package that was the ultimate procedural package, Houdini. About 9 months ago I decided to give it a go but was talked out of it because "there are no jobs in Houdini". Since then I tried to migrate to Maya but found it was not as PROC as max. Then there became a demand for Houdini animators, so I decided to make a move to the package that I believe thinks like I do..... Hope I made the rite move, there are no Houdini jobs in my city of Brisbane (it is a Max and then a Maya town)

Ok now on to the question. What I am trying to do is find out how the normals have changed from before to after a displacement. I have made a vertex shader that has a veins pattern fed into a displace-normal and then the normal-out into a dot product VOP and from the global N to the other input of the dot product. I have read that the normal-out of the displace in a vertex shader is inactive but this gives you an idea of what I am trying to do.

I have found it handy to put the output of a vector or a float into the vertex colour to visualise the effects of different parts of the shaders.

This is part of a larger problem I am trying to solve but I want to solve it one step at a time. In high school I did the standard maths and I am discovering all the geometric equations a little daunting but I am slowly getting the meaning behind some of these maths terms and vector operations.

I hope you can help.