Interesting question.
concerning mould differences, e.g. there are different moulds of 3001, where the walls got thinner and to still have cluth-power, some very small filltes have been added. those are not modeled, we kept the 4 LDU thick part. That is fine
Whenever an understud is held in place (reinforced) with a fillet, I would tend to have this modeled. As it is also part of the geometry that prohibits a bar or something else going into this place.
If such a thing is completely invisible, as it is part of an animal consisting of two distinct halfs, I would leave it up to the author, but those can be skipped IMHO, if it is not a transparent part, e.g. like the deer.
An example for a considerable mould change here is the "Duplo Roof Sloped 33 4 x 4 with 9 Bottom Tubes with Awning Overhang". This has two moulds (and design-IDs), which are for the basic Duplo build practically the same. However their underside is very different. 9 versus 5 anti-studs. So this is definately a "yes" to be modeled"
https://library.ldraw.org/tracker/24487
https://library.ldraw.org/tracker/24647
Examples where the reinfocement could be skipped are the "blates" the two plate thick "baseplates" those have usually some diagonal reinforecements 20-30 LDU wide and 1 LDU high, so basically they just make the top of the plate thicker, those are not necessary in my view. Mecabricks models them, but those are not necessary IMHO.
BR
Gerald
concerning mould differences, e.g. there are different moulds of 3001, where the walls got thinner and to still have cluth-power, some very small filltes have been added. those are not modeled, we kept the 4 LDU thick part. That is fine
Whenever an understud is held in place (reinforced) with a fillet, I would tend to have this modeled. As it is also part of the geometry that prohibits a bar or something else going into this place.
If such a thing is completely invisible, as it is part of an animal consisting of two distinct halfs, I would leave it up to the author, but those can be skipped IMHO, if it is not a transparent part, e.g. like the deer.
An example for a considerable mould change here is the "Duplo Roof Sloped 33 4 x 4 with 9 Bottom Tubes with Awning Overhang". This has two moulds (and design-IDs), which are for the basic Duplo build practically the same. However their underside is very different. 9 versus 5 anti-studs. So this is definately a "yes" to be modeled"
https://library.ldraw.org/tracker/24487
https://library.ldraw.org/tracker/24647
Examples where the reinfocement could be skipped are the "blates" the two plate thick "baseplates" those have usually some diagonal reinforecements 20-30 LDU wide and 1 LDU high, so basically they just make the top of the plate thicker, those are not necessary in my view. Mecabricks models them, but those are not necessary IMHO.
BR
Gerald