Surface to solid

Select the import feature, then do 'Edit>Solidify' or 'Edit>Thicken'. If neither works, you have a problem with surface integrity. If you see any pink edges in the quilt or if you go to 'Info>Geometry Checks' and you find a list of gaps in the quilt, you have a problem with the imort feature. If you have Import Data Doctor functionality, this should be turned on before you do the import and it can automatically fix many problems and analyze and recommend solutions for others. If you don't have IDD, you can select the quilt, do 'Edit>Definition'. Then do 'Geometry>Heal Geometry'.