Hy,
 
There's a strange behaviour on survey points :
 
I want to give a "survey info" Z value of 0 on a few points (that are on the ground).
So I check only the Z "survey info" value in tracker param window
but each time I come back on this tracker after editing something else
the value has changed !  
...the Z has come back to it's first (computed) value.
As if it was impossible to force Z to 0 ...
 
Strange because I did it on another scene with success...
Note : There's no relation, the camera is free and Z is the vertical axe.
 
Anyone knows where I'm wrong ?...    
 
MM 3.0 + XP Pro

Hello,
This sounds weirds. Can you try another workflow:
First be sure to have define a coordinate system with Z as up axis
Then create a point relation with all the points you want to use and set its value as fixed and value 0.
It should better work this way.
Bye

Thx for answer Ronald  
but I tried to create a relation with all track at Z=0 but it allways make strange camera solving : camera bounce everywhere in 3dsmax,
very unstable !
And I don't master very well coordinate system (I'm a beginner)  
because it's quite difficult to navigate in MM's 3D space...
 
Theoricaly the survey mode allows us to specify a value... :!:  :?:
 
Maybe my tracks arn't good enough (a few red ones remaining...)...
 
Fabrice

In fact, if you only supply Z coordinates of some points, the solver may be unable to create a coordinate system out of it.
 
The solution for you is to define a coordinate system based on some tracks.
 
The 3D navigation has been improved in v4, anyway you can select a track on select the Look At comand to orbit the camera around this track to help you.
 
You can send us your project if you want more assistance.
 
Bye...