Inventor: tangent connection or smooth connection?
In Inventor you can create curves and surfaces with different degrees of smoothness. This feature has been present for a reasonable amount of time in the most recent versions, and we can find it both in the sketch environment ("smoothed" constraint) and in the modelling environment...
The advantages of PDF 3D
3D graphics puts the product in your hands, you navigate it and identify the various parts and then link to other detailed information (data sheets, installation instructions, etc.), anyone can view the PDF3D because Acrobat is practically everywhere, and those who don’t have it, can easily download it.