Modelling the inside of parts

[Ronald Vallenduuk]

Under what circumstances and to what extent should the inside of a part be modelled?
The reason I'm asking this is that I'm working on the PF Track points and their 9V counterparts have the entire inside detailed in the part; the bottom cover is a complete part and everything below it is modelled too.
Personally I don't see any use or need for these details. That bottom cover is not intended to be removed and I'd say 99% of owners never have and never will.
In comparison, for example the PF motors don't have their insides modelled; the shell components are only drawn as far as they can be seen without disassembling the part.
Are there rules or guidelines about this? My intention would be to build the track points like the PF motors; only model what you can see. This would also affect the Monorail track switch that's being discussed elsewhere.

[Chris Dee]

Ideally I would like to see the part modelled as it is moulded, but if it is not possible to see the inside and you don't want to damage a sealed part then it is acceptable (IMHO) to include false internal surfaces. The part should be a complete solid and the separately moulded components should be created as separate parts. So in the Monorail Points example, the underside cover should be created as a separate part, but it does not (necessarily) need to have all its hidden detail modelled.

[Max Martin Richter]

I try to model the complete part as it is moulded. But when I have a damage an expensive part, then I try to ask some of my friends, if someone has the part with scratches or evenly completely damaged. (See how the the 9V Train Speed Regulator was done and note that the inside is still simplified.) And if it is not possible to get an damaged part, then I would go the way an model only the outside and make an 'fake' inside, so that at least the part is closed and has no gaps.)

/Max

[Michael Heidemann]

This is the same way I have done such parts in the past.