Restrict Camera movment within a angle range and along an axis

[udaydutta]

Victor, I am working on a smart rendering project using JSModeler library. I want to restrict the rotation of my model ( By camera positioning) along an axis and within a angle range. Could you please give me any tips or suggest any example code? Also I am using a skybox to add a background to the scene. The problem is, whenever I am changing the viewing angle the zooming is getting reset and skybox cube is being shown on the screen. How I can persist the zooming level on the scene even though I change the viewing angle?
Any clue or code example will be really appreciated. Thanks and regards.

UCD