Carrara's modeler is "meh" to put it lightly. It's polygon tools are fairly weak, and it does a few "nurbs-ish" things. And both ways of working aren't exactly fully interchangable.

For box/poly modeling use Wings3D, Silo, or Modo, depending on how much you care to spend. If you think nurbs is more your liking, then Blender, MOI, Rhino, C4D, or Maya.

The question was about modeling, yet you're probably going to want to render too...

In that case, consideration of Carrara comes back into play. That's where its redeeming qualities come in. (Decent as a rendering engine, and ok at animation. Just don't model much with it, unless you like workflow slow and tedious.) It's possible to import a model in .obj format, texture it and stage it, and get nice results with much less figuring and messing around than it takes for most other apps. (It really is drag n' drop for most things. Working with staging and mats is the opposite of its modeler.) If you do look at it, consider it as complimentary to whatever modeling app you choose.

The other pay-for rendering apps are just as good if not better than Carrara, but keep in mind the price and learning curve. It's not going to get any easier, and to get more you're going to have to pay quite a bit more.

And if you don't want to spend anything on rendering, I'd suggest Kerkythea(non-commercial), Blender, or POV-Ray. Just be prepared to put more time into figuring them out.

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Barbequed Pixels?

Your friendly neighborhood Wings3D nut.
Also feel free to browse my freebies at ShareCG.
There might be something worth downloading.