Smoke visible through objects

Seems like there is a problem with the order of rendering when it comes to smoke particles. Although I have objects blocking the view, I can still see campfire or furnace smokes coming from them.

Transparency is something 3D engines have a problem with. The engine doesn’t know which is in the foreground and which is in the background so one overtakes the other depending on the camera angle. Sometimes this causes what should be in the background to be in the foreground, especially for particles which are 2D sprites that always face the camera.