Ni- and Co-based inverse opals can be considered as a three-dimensional network of nanoobjects connected with each other by elongated crosspieces (legs). Inverse opals magnetic properties strongly depend on the legs aspect ratio which can be tuned during fabrication process. We study this dependence by means of micromagnetic simulations. We have found the range of ice-rule validity and studied limiting cases of high and low legs aspect ratio. We also investigate the value of the transverse magnetization component which should appear if the external field is applied perpendicular to one of the legs. Legs aspect ratio which corresponds to the maximal value of this component has been found. Finally, we calculate the dependence of the magnetic form factor on the external field for considered models. These results can be directly compared with experiment.