While it is true that simple modeling like this is adding unseen faces and such, it is unlikely that it will affect performance as much as I think they're making it sound. Gamestudio uses an effective culling algorithm that does not render unseen geometry.
Instead, your performance issues are probably related more to the fact that the simple modeling is using more video memory. More shapes take up more space. If your intended user is like to have a high-level system, this shouldn't be a problem.
There is a trade-off here: simple shapes tend to be easier to texture, both for you (the creator) and the computer (the renderer).
My recommendation is to try making a few "complex" models and compare them to your simple models. There's a couple of things you'd probably want to consider:
1) Am I getting a noticeable performance increase?
2) How long is it taking me to make these new models? Is the extra time worth the gains?
3) Do the models look good? Are they matching my intended style? Are the textures looking okay?
See how things go. Looks good otherwise!
(Edit) Sorry, I saw something else I wanted to address. As long as you are using the same textures repeatedly, there shouldn't be a performance decrease. The texture images are loaded in the video memory once, then used over and over again on the models. Again, this might be another reason that simple modeling is good, since you do not need an individual texture for each model.
I am one of the students asu was talking about, and if I had read what he said I would have agreed with you as well. but he didn't state what the true problem was. the problem isn't as much the fact that his buildings are showing extra faces etc. altough some of them are 2 times as big as they need to be since the half of the pollies are invisible.
but that isn't as much the point as this.
like he said they finished around 90 buildings. and all 90 buildings have their own texture, since they want every hous to be difrent and are using no window or door objects they are doing this with textures.
so this means they have 90 textures of 512 x 512 x 300 dpi alone fore the front of the houses, then 10 defrent textures fore the ground alone also all 512 x 512 x 300 dpi.
then about another 20 of those textures fore the sides of the houses again 512 x 512 x 300 dpi. and then 5-8 512 x 512 x 300 dpi textures fore the roof.
with a few calculations done by asu him self the textures alone will taake up 200 mb's of space alone when the city is done.
this is with out the 200 buildings, wich are all unike so that means 200 houses need to be loaded in not counting the gates and walls.
then there are all the other things like stones and trees, wich are done efficiant and I have no problem with those.
and afther all that we need to put in our own models to make the market interactive not to mantion a few small game events.
so to sum it all up, it's astimated that we will have the folowing when the program is finished with out even adding the game element.
- 250+ textures of 512 x 512 x 300 dpi
- 210 buildings of 60 - 120 pollies each
- a couple of extra objects
- 1 moving moddel with her own textures
- and more random stuf that isn't seposed to be there
and I'm sure you would agree that this is just way way way to much.