any cad tool will work with s3d as long as it can export STL
out of free app's blender is the most stable & powerful one, but has a
very steep learning curve .. it's best free thing to do modeling of organic stuff .. it's a mesh only modeler (don't understand solids)
freecad is organized as engineering modeling tool but is not very stable & fast, you can do lot of stuff quickly, you can generate professional designs, can work with IGES and STEP files, it understands both meshes and solids, development is active and it's getting faster and more stable every day, upgrade regularly
Art of Illusion is also very good modeling tool, not too fast (java) but decent and simple to use with powerful scripting possibilities (I use it for e.g. to create involute gear designs)
openscad - extremly fast and super powerful if you don't mind "coding your part" - not for "designers"
... you design your part in text editor
all of them work on macos
now, there are web based ones:
- fusion360 (very powerful, free, popular in 3d printing world)
- onshape - from the makers of solidworks, extremely powerful but free version makes all your designs public, if you want private projects you have to pay, it allows for multiple ppl to work on same design in the same time, my favorite free tool (I don't care that designs are public, I share them anyhow)
- tinkercad - very popular among noobs, allow super easy creation of basic stuff, allow super easy editing of stl files etc etc.. terrible for very complex stuff but for complex designs you outta go with fusion360 or onshape anyhow
there are more but these are the most popular ones .. there are also student / crippled versions of some professional packages that get available from time to time but I tend to avoid those as full versions cost arm and a leg
gcodestat integrates with Simplify3D and allow you to
Calculate print time accurately (acceleration, max speed, junction deviation all taken into consideration)
Embed M117 codes into G-Code
Upload your G-Code directly to Octoprint
open source and unlicence