yes, this kind of thing is very easy to do in MEL or Python. (you could do it in C++ but that's probably 100x more complicated overkill).
First you just have to parse your text file, then you have tokenize the data somehow, depending on how it is formatted, then you have to create the plane based on that data. Each of these is pretty straight forward.
Obviously we don't know your text format, so this is an example file I'll use, saved as "d:/work/plane1.txt":
vtx 0: -4, 0, -5
vtx 1: -1, 0, -5
vtx 2: -1, 0, -3.5
vtx 3: 3, 0, -3.5
vtx 4: 3, 0, 1
vtx 5: 1, 0, 1
vtx 6: 1, 0, 0
vtx 7: -2, 0, 0
vtx 8: -2, 0, 2
vtx 9: -4, 0, 2
and here's an example in Python (as MEL is much weaker for doing this kind of stuff, (but still completely feasible if necessary)):
vtxPnts = []
# first, open our plane text file
# (if we had several we could put this in a for..loop)
with open('d:/work/plane1.txt') as f:
for line in f.readlines():
# the exact code here depends on your text file formatting
vtx, coord = line.split(':')
point = [float(x.strip()) for x in coord.split(',')]
vtxPnts.append(point)
# now we have the point array, create the polygon "plane":
cmds.polyCreateFacet(point=vtxPnts)
and it's basically as simple as something like this.
obviously it becomes more complex if your file is in a more complex format, or JSON, or you have MULTIPLE planes or additional data in there to handle (colours, materials, etc..) but this example just shows you how simple it is to parse a file, extracty some data and create polygons in Maya.
I hope it helps.
