Greetings, I am making 3D plots using persp3d, and would like to set z-axis limits and make axis labels (the automatic numbers at tick marks) bold. I have tried "zlim", but this does not seem to force the plot to restrain itself within certain bounds (e.g., 0-1). The surface I am plotting (z values) does contain some values outside the range I am setting. Maybe this overrides the "zlim"? Is there a way to fix this without manually removing negative z values? Also, is there any way to make the numerical axis labels bold, or generally darker or larger? My code currently reads: xtemp <- 6:22 ylight <- seq(from=-7.5, to=-5, by=0.5) wDeltaT <- 0 code <- 1 grid.tld <- expand.grid(temp=xtemp, logwm2=ylight, DeltaT=wDeltaT, code=code) YaoRasPred<-predict(YaoRas.Distribution.T.L.DT.gamm$gam,newdata=grid.tld,se.fit=T) Rel.Dens <- matrix(YaoRasPred$fit, nrow=17 , byrow=F) # use predict instead here library(rgl) persp3d(xtemp,ylight,Rel.Dens, zlim=c(min=0.0,max=0.032),xlab="",ylab="",zlab="",col="gray") Thanks for any advice, and thanks again to Duncan Murdoch for suggesting persp3d for my purposes! Sincerely, Paul Simonin