No valid positions to place object found when attempting to place many small objects on the same plate or bowl

[Gabriel Sarch]

Hello,

I am using ai2thor version 3.1.0 (but have tried later versions as well). We have found a problem with interaction when attempting to place many small objects on the same plate or bowl. We have found that when one or more object (e.g., slices) are already on a bowl or plate, attempting to place another slice on the plate often causes action failure with error message "No valid positions to place object found":

<ai2thor.server.Event at 0x7fd33070e4f0
    .metadata["lastAction"] = PutObject
    .metadata["lastActionSuccess"] = False
    .metadata["errorMessage"] = "No valid positions to place object found"
    .metadata["actionReturn"] = None

For example, below I am trying to place a second potato slice in the bowl which, based on the image, should fit in the bowl.

We have also found this error persists when not only specifying an x,y position but also directly calling the simulator via:

self.controller.step(
                action="PutObject",
                objectId='Bowl|-01.86|+00.92|+01.80',
                forceAction=True,
            )

I have done a search of previous issues and think it may be related to ai2thor free position as stated in this: #367. Is that correct? If so, are there fixes/workarounds for this issue?

Any help with this would be greatly appreciated! Thank you so much!