Please Ahmed, You only need to post your comments and questions one time in one place.

Trust me, we ALL see EVERY post you make.

Furthermore, this particular group is for ideas or feedback you have for GrabCAD in general. It is not for design questions.

You want to DESIGN 3D models for Robots and machines....So why the need for dimension and ALL the parts.....Designers MAKE/DESIGN those parts themselves...

Start by reviewing the catalogs of a manufacturer, such as Kuka, which are available on the internet and have general dimensions, arm reach (working area), supported loads, accessories, etc.

The 2d-drawings for AR4 Mk2 is also available:
https://www.youtube.com/watch?v=RckTj0h5LnE
https://www.anninrobotics.com/downloads
if you want to practice with 'real' components/dimensions.

Please do not spam by posting the same question in multiple groups.

Also this group is about feedback for GrabCAD community, not personal questions.

Please continue from your other conversation: https://grabcad.com/groups/robotics/questions/designing-3d-models-for-robots-machines

I have one as an example, I attach it in pdf.
PS: The CAD model of that robot is in the GrabCAD library.