How to convert a certain voxel to be occupied?

[HangX-Ma]

Hello sir, when using your OctoMap package, I met some problem about updating a certain voxel property.
I converted a certain voxel to be occupied with the code below, but my path planner reflected that this voxel changed nothing.
I have read your manual online. If I understand your annotation correctly, this code should have worked well.
I hope you can get me out of the 'code trap'. Thanks a lot !

setCurrNodeObs(octomap::OcTreeKey &key, std::shared_ptr<octomap::OcTree> &tree) {
  tree->updateNode(key, true); // 'true' if the node is occupied
  tree->updateInnerOccupancy(); 
}

[UPDATE 2022.03.14]
I need to add some info about how I recognize a node as an obstacle.
I have checked some nodes' occupancy value, and the result seems not like I thought previously.

bool isOccupied(octomap::OcTreeNode* currNode) {
  return currNode!=NULL && currNode->getOccupancy() >= 0.5;
}

@ahornung [question]