# Translating a plane

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I have these bounding plane and I want to give them a path, is there anyway I can multiple the plane's information (A,B,C,D) by a matrix to move it properly, or am I better off just multiplying the one point used creation of the Plane by a translation matrix then recreating the plane with the normal and the new translated vertex? -THACO

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Well, you have:
x.A + y.B + z.C = D
(where (x,y,z) is the old origin)

The new equation will be (assuming (A,B,C) is the normalized plane normal):
(x+tx).A + (y+ty).B + (z+tz).C = D'
(where (tx,ty,tz) is the translation, D' the new D, normal is unaffected by translation, so A, B and C remain the same)

rewrite:
x.A + y.B + z.C + tx.A + ty.B + tz.C = D'
=
D + tx.A + ty.B + tz.C = D'

so in the new equation (A', B', C', D'):
A' = A
B' = B
C' = C
D' = D + tx.A + ty.B + tz.C

Feel free to correct me if I'm wrong...

Tom

Edit: I would suggest going for the vertex/normal implementation anyway. That would allow you to rotate as well. I'm not sure if that is possible with just the equation.

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