animate modifications to a mesh, other than movement?

I’m trying to animate a light beam going through a lens, like focusing sunlight through a magnifying glass. Howver, when I try to apply a “point” to the beam by modifying the light beam mesh (and hitting Ikey at a frame downstream to apply a keyframe), the change is applied from the very first frame. In other words, I’m trying to animate an extrusion & scaling starting from a specific keyframe and not throughout the whole animation. What am I missing? In general, how do you animate changes to a mesh, other than just movement?

thanks

Just put an I-Key (keyframe) at frame 1 then another (unchanged) at the frame where the change starts.

%<

Well, I found out what I need to do is “Animation of Deformations, Abosoute Vertex Keys” but apparently Blender 2.4 has changed this interface a bit. How do I set the reference Key and see the Vertex type IPO?

thanks

You use the shape keys - in editing (f9) (these have replaced vertex keys)
click the shapes tab (next to the modifiers tab) and add key
There is a topic I read last night in the blender general forum but I cant find it at the moment that explains how these work- do a search

Cheers

DSD

RVKs are probably what you need. Look at this link for basic info:

https://blenderartists.org/forum/viewtopic.php?t=58669