Think about this phrase: "How did the sculpture look?"
If I asked you this, how would you respond? Would you tell me what it looked like? Or would you tell me how it impressed you? I think this question is asking how something looked, in the sense of it appearing like something else. Simply saying "how" something looks can be vague since if could include another kind of question that would be worded differently in Korean.
That is my interpretation, at least.
IMO, It is closer to the English present perfect which describes an event that started in the past and is continuing now [= has been and still is]
생겼다 => has (/-ve) appeared and still appear(s), in reference to the moment the statement is made.
생겼었다 => appeared/used to appear, describing an event that happened in the past and has no longer any connection to the present.
생겼었 었다 => had appeared, describing an event completed before some reference-point in the past.
생겨요 => is/are appearing or becoming, describing an event developing/progressing right at the moment when the statement is made
Translation is situational and is difficult to give an 1:1 account each time, but this is the closest I come to understand Korean tenses.