[R] help with cube3d cube size

[Duncan Murdoch]

Mark Kimpel wrote:
> I'm using the command below on an open3d() object to create a shaded
> cube. Changes to myScalingFactor do not effect changes in the size of
> the cube. What is the correct approach? Mark
>
> shade3d(translate3d(cube3d(identityMatrix() *
> myScalingFactor),-6,1,-1),col="green", alpha = 0.2)
>
>   
Homogeneous coordinates are strange.  Your

identityMatrix() * myScalingFactor

produces a matrix that has the same effect as not multiplying.  You need

scaleMatrix(myScalingFactor, myScalingFactor, myScalingFactor)

to get a size change.

Duncan Murdoch