Can someone please explain why position vector of index point works on ‘set position’ offset? but not on position? If I put manually vector xyz position numbers from spreadsheet of any point into ‘vector’ node it works but won’t read it this way. I’m new to blender so not sure if it’s a silly question… 
Update:
How to extract point’s vector position from index to constant value?
cheers
Hello and welcome to blenderartists !
Yes, if you look at the sockets, one is in diamond shape, the other is round.
The diamond shape means that the value is a “Field”. A Field means that the value can varies.
When you use it in the set position node, each point can be set with a different position. Because the Field can have different value for every points.
The round shape is a constant. The value is always the same.
The transform node translate the whole geometry by an unique value, it’s not per points. Therefore it’s not possible to use a field on these sockets.
So yeah, Fields and constant values are very different, even if the color is the same.
You can have a Constant output plugged into a Field input, that’s OK ! but the opposite doesn’t makes senses.
Hope that helps, I tried to explain it the best I could, but this can be a bit confusing, maybe someone can provide a better explanation if needed !
Good luck !
@sozap
Thanks mate, yeah that helps.
Wouldn’t have an idea how to extract a point’s vector position to constant value though, would you?
I’m not sure it’s possible. You need to find another way around.
I think what you need to do if you want to connect line between points , is to start by instancing the curve lines into the points, then realize instances (the lines) , and then take the end point of the curve and give them another position ,
It’s a bit late for me now so I won’t look into it, but maybe someone else can help you further !
Good luck !
Solution:
thanks
cheers, put me on the right track, 
