Attibute new dimensions to my object

New on Rhino, I begin the BASICS.
I try to attribute desperately how exact dimensions(size) to an object on my scene. The panel properties does not allow it me.
I shall like I can create any object (box, rectangle, circle) and then be able to select it and find the command which opens me a panel allowing me to bring in the dimensions(size) in cm or mm.
Thank you and saddened if it is a récurente question but I don’t found of threads on this matter.

Rhino is not a parametric modeler where you can change the size of an existing object like the radius of a circle for instance and have the circle update. There are plugins that allow this type of interaction but they are not available on Rhino for Mac just yet. Grasshopper and possibly the BoxEdit command in Windows Rhino are two options if you have a PC as well. If you are only using Mac Rhino, you can scale objects or move sub-objects numerically as one possible approach. Post a model with specific instructions on what you’d like to do and I can try to help more.

Thanks Brian,
I haven’t model.
I work on Cinema 4D an MoI, and i need often to change design and dimensions to my objects. Just selecting the object and change directly parameters in mm or inch or cm in a panel properties. it’s more easy than calculating scale in Rhino for mac.

Why i can’t install BoxEdit command on Rhino for mac ?

I too have used Moi and like this ability. Something like this should be implemented in Rhino.

That’s only available in Windows Rhino right now but it’s on the list to implement in Rhino for Mac. In short, it’s a plugin that we install with Windows Rhino that needs to be ported or rewritten for OSX.