Tips of the Week

Here is a list of all past and present Tips of the Week, organized into categories. Newer tips should go to the top of their respective categories.

MaxScript

Getting properties takes time (additional time for custom Parameters, and even more for Custom Attributes). If you must access them repeatedly, assign them to a variable.
Equality tests take time (though short). Try not to use "if <val> == true then" or "if <val> == false then". Instead, use "if <val> then" or "if not <val> then".
if <test> then is different than if <test> do - do does not take an else clause and will execute immediately in the Listener, while the former will wait for an else clause input and will appear to hang the Listener.
Instead of initializing an empty array and appending based on a test, you can just use

newArray = for <member> in <set> where <test> collect <member>

The W component of a UVW is always available (just turn your float2 input TEXCOORD into a float3)- you can use it to store an arbitrary value (such as vertex alpha).