background of the 3 dimensions?

how to make background for the 3 dim from cammand?

Your question is vague. What do you mean by "make a background"? Do you want to change the color of the model space screen? Do you want to add an image (ex. - sky) to use as a backdrop for a building?

And what does "from cammand [sic]" mean? Do you want to do this from the command line?

Dimstyle, Text tab, Fill color: background mask.