If I am correct, "Tvaṣṭṛ" seems to be synonymous with Viśvakarman, while "Tvaṣṭā" is the name of an Asura. It seems that both are identified as Prajāpatis, and this has me wondering: Are these two deities identical?
1.Viśvakarman, the architect of the gods. He had a son named Triśiras and a daughter called SamjnA, who was given in marriage to the sun. But she was unable to bear the severe light of her husband, and therefore Tvaṣtṛi mounted the sun upon his lathe, and carefully trimmed off a part of his bright disc;
- The Sun
is the name of two asura priests.
'Tvaṣṭā' is the prathama vibhakti ekavachana of 'Tvaṣṭṛ'('pratipadika') and these two words therefore have identical meanings.