Recently much attention has been paid to multilayer inertial confinement fusion (ICF) targets, among them the targets with low-density layers. This allows one to get a number of interesting results using the presently existing and future facilities. This concerns the volume absorption of the laser radiation in a porous matter of the density higher than the critical plasma density, and the formation of the radiation absorption region under condition of increasing geometric opacity of the low-density matter. We consider the low-density foams, 3D nets, free-standing “snow-like” layers, and pseudo low-density layers. We use artificial foam as a convenient model to allow easier comparison of the experimental laser shot data and the simulation. The requirements to such layers are also analyzed. The methods of precision control of the low-density targets are discussed.