The Church strongly prefers that cremation take place after the full funeral liturgy with the body. The presence of the body most clearly brings to mind the life and death of the person and better expresses the values that the Church affirms in its rites.
From The Order of Christian Funerals, Canon 1176.3: This is the body once washed in Baptism, anointed with the oil of salvation, and fed with the Bread of Life. This is the body whose hands clothed the poor and embraced the sorrowing…Thus, the Church’s reverence and care for the body grows out of a reverence and concern for the person whom the Church now commends to the care of God…However when circumstances prevent the presence of the body at the funeral liturgy…it is appropriate that the cremated remains of the body be present for the full course of the funeral rites, including the Vigil for the Deceased, the Funeral Liturgy, and the Rite of Committal. The Funeral liturgy should always be celebrated in a church or chapel.