build-a-scene

Building a scene from code

The three properties, and why they get confused

A CoppeliaSim object has three independent switches. Almost every scene problem comes from mixing them up:

Property	What it decides	When it is wrong
dynamic	whether physics moves it (falls, gets pushed)	the scenery collapses on Play
respondable	whether other bodies collide with it	the robot drives through walls
detectable	whether a proximity sensor sees it	the sensor "doesn't work"

A scenery wall is not dynamic, respondable and detectable:

sim.setBoolProperty(handle, "dynamic", False)
sim.setBoolProperty(handle, "respondable", True)
sim.setObjectInt32Param(handle, sim.shapeintparam_respondable_mask, 0xFFFF)
sim.setBoolProperty(handle, "detectable", True)

detectable is the number one cause of "my sensor detects nothing". It is neither inherited nor set automatically: a freshly created object is invisible to every proximity sensor until you set it.

Decorative floors must not be solid

If you colour each room's floor with a thin box, that box must not be respondable or collidable. A 1 cm floor is a 1 cm step in every doorway, and the robot trips over it or gets stuck.

Leave them as pure decoration: not dynamic, not respondable, not detectable. The robot rolls on the real ground, not on the colour layer.

The default floor is 5 x 5 m

/Floor ships with the scene and is small for almost any floor plan. If your scene is bigger, delete it and create ground of the size you need, or the robot will drive off the edge halfway through.

Walls with doorways

A wall with a door is not one object: it is two segments with a gap between them. Generate the segments from the full line plus the list of openings rather than placing each piece by hand — that way the numbers come from one place and moving a door forces no recalculation:

def wall_segments(start, end, doors):
    """Returns the wall pieces between start and end, skipping the openings."""