Which 3d software to learn?

depends really whether you want renders or 3d construction drawings…
It comes down to cost and many other issues and the type of architecture your producing…

but most people use vray as a plugin for max.rhino.sketchup ect… There are some cheaper ones and some people just use plain old autocad…

just don’t get to good at it otherwise you might do it for the rest of your life…:cool:
and be aware a lot of it gets outsourced overseas just like construction drawings…

3D studio or Cinema 4D would be two popular stand alone apps, but perhaps a bit daunting to learn, but can produce exceptional photorealistic images. Artlantis is a more user friendly app, you could produce fairly good results, and I perfer it simply because it is not as hyper-realistic as the other two, it can look like a photograph of a model, more suggestive.
An alternative plug in for sketch up is podium, again very simple, but very slow.

I would echo missarchi’s comments about not getting too good at it, otherwise it is all you will end up doing. You will just be the “3D guy” in an office, which is not fun.

glad to see your upskilling. Unfortunately Autocad is as outdated as handdrafting was back when autocad was introduced. New products like Revit have seriously advanced the whole cad thing. The drawing now has the capability to produce bills of materials, parametrically deal with changes, send components to CNC for machining, do finite analysis, rattle off BER reports, the list is endless.
As for rendering ,Studio Max is the standard but there are faster cheaper and better packages out there ( See I dont work for Autodesk). I use Radiolab coz its quick and has great animation flexibility and I cant be bothered learning a new programme. Have a look around and if you find something more interesting let us know.