3D nonwovens can be formed using the air-laying principle. The fibers are deposited onto a porous mold and the web is then consolidated. Distribution of the fibers on the 3D mold must be regulated to produce a final product with the desired fabric evenness. This can largely be achieved by varying the local mold porosity. CFD modeling is used to calculate the required porosity in different regions of the mold in order to achieve an even fiber distribution, and the results are experimentally validated.