[mikl_plkcc]

It depends most on the suit quality and less on point counts.

For me, 1m - 1M - 3m shows a near GF hand that responder is supposed to bid 3NT with stoppers in other suits even when minimum, and 5m with extra strength. It shows at least a good 6-card suit.

For example,

♠QJ
♥A9
♦A5
♣AQ97632
is certainly a 3♣ after 1♥ response, partner is supposed to bid 3NT with a stopper in the other major.

♠KQ
♥AK
♦Q97532
♣A73
is rebid 2NT.

♠Q8
♥K6
♦AKJT97
♣AJ3
is rebid 3♦ after 1♥, even with only 15 HCPs since the ♦s are near solid and there is a good chance that the ♦ will run in 3NT.

♠K73
♥A7
♦KJ8654
♣A5
Although the above hand contains also 15 HCPs, the quality of the suit is bad so 2♦ is rebid.

♠Q75
♥7
♦32
♣AKQJT98
This is a borderline hand, since partner will not expect 7 good ♣s with 1♣ - 1♥ - 2♣.

[the_dude]

This auction is so space-consuming and awkward - responder has little room to investigate anything (particularly when the minor is Diamonds). Therefore opener must be good enough for responder to bid 3NT on any excuse. It's hard to describe that in terms of points ... it's more about tricks and good side cards.

Therefore, I tend to only bid 2m with anything up to non-exceptional 14s and bad 15s - I expect my partner to look at his hand and be able to figure out to invite on marginal hands that include Qx of my suit