I walk with my dog every day and during the winter, he wears boots that protect his paws from the salt, ice and snow.  However they become wet and I designed this rack to keep them organized and to make sur they dry as fast as possible.  I printed it in PLA but if you were to put it over a heat register, I would print it in PETG.  Make sure top and bottom shell layers are 0 and choose an infill of your choice with a percentage that looks good.  The one in the picture and in the profile is Grid at 10%, but Honeycomb looks good as well.