Specifying ticks in Asymptote 3D graph

Question

How do I create 3D axes in Asymptote with customized tick locations? For instance, I know that

xaxis3("$x$",-1,1,black,OutTicks(2,2),Arrow3);

produces an arrowed-axis with two intervals between -1 & 1, and each of these intervals has two subintervals. What if I wanted ticks at -1, -0.5 and 1? I've read the manual but frankly don't understand much of the graph3 section.

Answer 1

A tickmodifier (I do not know how it works) can be used (as in brokenaxis) to remove some automatic ticks. Another possibility is to specify the ticks values, as in the following example

import graph3;
size(0,200);
size3(200,IgnoreAspect);

currentprojection=perspective(5,2,2);

scale(Linear,Linear,Log);

real[] myxchoice={0,1/3,3/4,1};

xaxis3("$x$",0,1,red,OutTicks(myxchoice));
yaxis3("$y$",0,1,red,OutTicks(2,2));
zaxis3("$z$",1,30,red,OutTicks(beginlabel=false));

It is the same with graph (2D).