Relationship between Camera Calibration & Scale of Model

[morgand536]

Is there any relationship between the parameters of camera calibration and the scale of the output 3D model?
Since I have found that the scale in different output models is arbitrary,
and the scale will only become real world scale only when i apply at least 3 control points. 

[bigben]

No. Camera calibration only corrects lens distortion

[morgand536]

No. Camera calibration only corrects lens distortion

Then what parameters will affect the scale of the model? or the scale will always be arbitrary until it is scaled with at least 3 control points? 

[bigben]

a) known camera positions. Combination of distance and angles defines scale.  Without known camera positions you only have angles which is enough for defining shape, but not scale.

b) known distances in the object, either using markers/scale bar or transforming the final model by a calculated ratio to correct scale.