[The_Kaiser]

Hello.
I'm simulating a transient combustion of H2-air. I want to track the flame along a line, but I can't proper define the expression for it.
For the moment, I created an intersection of an isosurface with Reaction progress=0.5 and a symmetry plane. With this, I created a point with a minimum value in X-direction. The problem is, my mesh is relativ coarse and instead of 1 point, a get 2/3 (depending on the timestep).
I can't proper define the expression to create a point, that will be on a line in direction I'm interested in, with a value (Reaction Progress=0.5).
I tried it with
ave(Reaction progress)@Isosurface 1
creating a variable with this expression
Create point
Point->maximum value->my created variable
But it gives me all points on the line, not 1. Any idea why?
I would appreciate any help. ZThanks in advance