I use SketchUp as my main 3D modeling program. Competent configuration of components and groups allows me to speed up the assembly process.
I prefer working with Rhinoceros 3D+Grasshopper to create more complex shapes.
I use AutoCAD for drawings. This program allows me easily customize the graphics of the lines.
The drawings undergo additional processing in Adobe Illustrator as appropriate.
Choosing software is my first step of creating an illustration. Depending on the task I use: Blender (it is easy to set up and fast in rendering), Adobe Photoshop / Illustrator for post-processing images or for making collages.