there are two modes in planeless scanning with DAVID (to be set in the advanced settings):
UseRememberedPlanes True or False;
In a Reference scan David calculates the precise position of each single laserposition per frame (or time) and calculates a model of the lasers motion too and strores it.
UseRememberedPlanes set to True means: Starting with frame 1 or time = zero, DAVID refers to the stored single planes`positions. This means, the motion of the laser may own some inaccuracies as long as these inaccuracies are the same in each scanning process.
UseRemenberedPlanes set to False means: Starting at frame 1 ot time zero, DAVID assumes a steady, averaged motion between the start and the end position. This means the charakter of your motion has to stay exactly the same within a single scan too.
You have two options to set this starting point in your workflow with the parameter ScanStartDetectionMode (0 or 1):
0 means that DAVID assumes the beam to be exactly at its recorded start position when you hit the Start button and performs its motion from there on now. To use this option, you have to have a COM connection to a lasermotion controller to trigger the motion.
1 means that DAVID waits for the first visible light it thinks to be the laser. Detecting it, DAVID thinks the laser is at its startposition (The position detected (in the reference scan) to be the first visible laserplane). Here you do not nead a COM connection, but you always have to make sure that the laser at its actual start position is visible for DAVID (which may not be the case in planeless situations) So you should use some trigger object placed in the scene to guarantee that.
curious to hear from a guy dealing with other scanning deviced. We can learn a lot
Edit: noticed Khalid answered meanwhile. Please forgive doubled things.