[R] MCMCglmm Intersex covariance set to 0

Dear all I'm trying to examine the effect that the additive genetic covariance (B) between the sexes has on the predicted response to selection on life-history traits in the sexes. Using the method of Argrawal and Stinchcombe (2009) this is done by calculating the response to selection

[R] trying to fit a thin plate spline to a triangular plot

Hi Has anyone tried to fit a thin plate spine to a triangular plot before? I'm having trouble working out a piece of code to make it possible with three axes. I have done it before with two axes. I've found a package I prefer that makes triangular plots (plotrix) using the triax.plot()