didn't see the wood for the trees... thank you alec!

That works perfectly! Thank you so much.

I'm sorry, the command line is not displayed properly. It's

>plots[interactiveparams]('plot3d',[ln(20-d*a^2-g*m^2)+1/(m+1)*ln(0.1+0.2*a),m=0..3,a=0..3,labels=["m","a",""],axes=boxed],d=0..5,g=0..5)

(I typed it up from Maple)

Hope this works now