Hi, Why does this not work? The values inside the rotationMatrix() doesn't seem to change: library(rgl) for(i in 1: 10) { a2=i*0.1; b2=i*0.2; c2=i*0.3 print(c(a2,b2,c2)) UserMatrix = rotationMatrix(pi/4,a2,b2,c2) print(UserMatrix) } Yours, Atte Tenkanen