See the light in after effects.
Edit by : After Effects 3D lighting feature creates pools of light generated from light sources in 3D space - but you cant see the light itself or the cone it produces. Enter Trapcode Lux: a speedy plug-in that adds volumetric lighting effects to projects that require realistic spotlights, point lights, or stage lighting of all kinds.

Features:

Fast rendering
With Lux, you can see the light with less waiting: its a 3D effect without the long rendering times of 3D.

Multiprocessor Support
Lux takes full advantage of all processors (Mac & PC) and Intel hyperthreading.

Light Modeling
Select a Light Model for different light looks.

Non-Square Pixels
Lux handles non-square pixel Aspect ratios correctly, so youll have no unpleasant surprises.

Deep Color
Works in 16-bit and 8-bit-per-channel color depths.

Let Lux Do The Math
Internal 256-bit (64bpc) calculations for Smooth results.

Reach Comp Layer Option
Allows light from spotlights to reach a specified 3D layer in the comp. you can free download Trapcode Lux 1.1 now.