By the way, if you map out the interval relationships of the open strings of the three commonly used major open tunings (D, G and C) they look like this:

Open D (DADF#AD) = 151351
Open G (DGDGBD) = 515135
Open C (CGCGCE) = 151513

You can see that there's a "513" pattern in all three of them, and it's within that three-string cluster that the basis for most chord shapes will be found. And, once a chord shape is learned in one of them, the same shape moved to wherever that "513" cluster is in any other will give you the equivalent chord for that key. For example, say you have a shape fingered on strings 1, 2 & 3 in C tuning that gives you a G chord. Finger that same shape on strings 2, 3 & 4 in G tuning and you have a D chord. Finger it on strings 3, 4 & 5 in D tuning and you have an A chord.

You'll usually need to work out what to do with the other strings outside of the "513" cluster to make the chord sound right (damp them, play them open, or finger them) but the basic shapes within the cluster remain constant.