Yes, you can change the anatomical model in different ways.
- First, start with a static model so you can edit meshes (if you have a posable model, right-click and select "Clone As Static")
Since you want to edit the lung, and replace tissue property to Air in regions where lung is deflated/smaller, I would clone the lung mesh, and then edit the clone. You can scale/stretch it using the Move tool. In addition, you can achieve quite detailed/complex deformations using the Morph tool.
Then, you can assign the old lung entity to Air, and the new (morphed) lung entity to "Lung". With the voxeler priorities, you can then make sure the morphed lung overwrites the old lung (but not and other tissues). So, you could use following priorities:
- all tissues except old/new lung: 3
- new lung: 2
- old lung: 1
Regarding your second question, how to measure the distance, I would propose you slice or cut the model. You can then measure the distance in the slice. You can also sample it at different positions along the z-axis.