To make a good glass you
must know about a few things. Not only the material is important, but
also geometry of your object and lighting.
Your object which will
have glass material must have its thickness, without it no glass will
look natural. Usually you make glasses using one or more splines and
lathe modifier. So when you prepare your splines make both sides of
your object at once (look at picture below).
Ok, object is ready. Now
the lighting. Almost in all scenes you use more than one light source,
and also for good glass you need a few lights. I usually use one strong
spot light and 2 or 3 darker spots as fill lights. Also you can put
one or more omni lights to make more speculars (glass material is highly
specular). To do so go to omni properties and uncheck "Affect diffuse",
leave only "Affect specular" on. Now use Place highlight tool
to position your omnis so they produce speculars on proper areas of
your object. Pictures below shows how I put my lights.
And finally the material...
Go to material editor and make material with parameters similar to those
on picture below.
I prefer metal shading
for glass material, but blinn shading may work ok too. 2-sided material
produce much more realistic glass so turn it on. Diffuse color should
be rather dark, perfectly transparent glass should have black diffuse
color, every change of this color will tint your glass. It is very important
to keep opacity of your material at 100%.
The most important part
of your glass material is refraction map - use standard in MAX 2 raytrace
texture. You may experiment with it's parameters to improve rendering
time and quality. For rendering time the most important setting is trace
depth - the higher value here, the longer rendering time, but if you
reduce it too much render quality will be very poor (black areas on
parts of rendered picture may appear). Use 60-95% amount of raytrace
map - depending on how transparent your glass should be.
can make a test render to check how good your glass is. For test renders
you may want to turn off antialiasing to speed up rendering. Test render
should look similar to this one:
You see lots of pixels
with different colors that look terrible. This is because there is no
antialiasing on edges and surface of the glass. If you turn on antialiasing
in rendering preferences to improve edges quality. And to improve glass
surface quality turn on Supersample in basic material parameters. But
remember that both antialiasing and supersample increase rendering time
And yet a few words about
glass: some areas of rendering above look too clear. Glass is highly
refractive, but also reflective material. You can apply raytrace texture
for reflection map, but combining raytrace map for both reflection and
refraction is a killing combo for any CPU :) So you can fake some reflections
using bitmap with environment/spherical mapping. Use some landscape
texture preferably with dark colors for best reflections. Amount of
those reflections you must find yourself because it is different for
every material and bitmap.