Solidworks AutoCAD Inventor 123D Sketchup

What do you mean by "works with STL files though? Do you want to export as STL, import STL, modify STL?

I have 123D and sketchup. Sketchup requires a plug in to export stl(s) and I had issues with it so I'm using 123D now. Neither will open stl(s) but 123D comes with a 3d print utility that will open stl(s). All I've done was open and look at one so I don't know the printer utilities functions beyond that.

There is a beta of 123D that is supposed to run a bit better. (Thanks for tip @Jstarne) I just got home so I haven't checked it out yet. 123 is an autodesk program (I think they make AutoCAD too, I'm not sure) I've not looked into Solidworks or Inventor at all yet.

In short, I've had great success with 123D Design.

Yes AutoDesk make AutoCAD and Inventor.

123D is easiest to use in my experience. It's what I use to make the basic structures. This is coming from someone who has professionally used AutoCAD for 15 years (well, 15 years in 4 weeks or so). It makes it easy, it is quick, it does most of what it needs to do, it's free, and it comes with cloud storage and the ability to modify your designs from any PC with Chrome as the browser (and good enough spec).

Once it's done I export it to Inventor and AutoCAD to fine tune where necessary (so far it hasn't been) and to produce images etc. of the parts.

From my past experiences, Inventor Pro is one of the best 3D programs you will find. It allows for everything you can think of, but the problem is that it takes a long time to learn and costs I believe $1000. For this reason 123D would be recommended.

I have a few parts that I have been wanting to print for my robot, but I haven't desighned them yet because I don't have a 3D printer and I doubt there is any in the area. I wish I knew of a service that would print my parts for me. As for I have been thinking about printing them for a while.

I've downloaded the 123D Designer and also 123 Make (Creates 3D pictures) The basic programs are free but can be upgraded with extra goodies like free prints of your designs. Once a design is finished you can save it either as Rich mentions in the Cloud or even on your own system. There is an option to output the file with the .stl convention.

After the file is created as a .stl file I load the image into the ReplicatorG 3D print program that then converts the image in a .GCODE file where final print controls can be tweaked like extruder temp and other things then convert the resulting file into a file that is placed into a SD card that is then inserted into the card slot of the printer microcontroller, whew !

Then some time later you get to see the results of your design efforts.