I think that we're both talking about different things here. I was looking at it from the point of a static model. IE - you divide up all the areas of your level into chunks that you draw / don't draw at certain places, and you use a function like this to draw large, texturally diverse areas at once. Static stuff only, not set up as some kind of animation hierarchy.That's not true - the purpose of being able to combine multiple models into one and be able to add translations and transformations on the fly to the added models is to provide an alternate mechanism of an animated model - a vehicle or a character, for example. And having a single texture for those is mostly exactly what you'd want.
You can do this currently to some extent, but you can't draw models with multiple textures in one larger model, so it's only useful for many objects that share the same texture, and often, those objects are not always going to be placed close enough together to take advantage of being grouped into a single model.
Edit: I already said that.
Of course, I'd love to see some kind of native 3D animation support / help added to Game Maker - even something basic. Not being able to easily animate groups of models in 3D is one of the main reasons why I haven't really done much with it in a while. It's incredibly discouraging to look at coding a (probably slow) animation engine for even simple games, when other game engines out there have that stuff built-in, ready to load up animations directly from your 3D software. (Before Mike sees this and thinks I'm trying to start a riot here!) I know Game Maker isn't headed towards this level of 3D support, and I don't expect it to... but some kind of options, even support for loading basic model file formats, would be nice.