What is the best way to create trails? If I have a simple mesh and I want it to leave a trail behind.

The simplest way would involve that object to constantly create (add object) a plane with a halo texture… so that when your object moves the halo follows him…

You could then make that halo object have an IPO of it’s own to fade away and finally dissapear… :wink:

A more advances trail system would involve some python to modify a trail object’s vertexes in real time…

Using halos is the simplist and most reliable way of making trails in Blender.

Blender only gives very limited mesh information in realtime though, so if you were using Python to modify an object’s vertices, you’d need some way of making sure you’re moving the correct vertices. (One of Blender’s biggest limitations, IMO.)