Update Volumetric-Lighting.md (#402)

Fixes https://fogbugz.unity3d.com/f/cases/1238592

Author: JordanL8

com.unity.render-pipelines.high-definition/Documentation~/Volumetric-Lighting.md

@@ -1,6 +1,6 @@
 # Volumetric Lighting
 
-The High Definition Render Pipeline (HDRP) includes a volumetric lighting system that renders Volumetric Fog. HDRP also implements a unified lighting system, which means that all Scene components (such as Lights, as well as opaque and transparent GameObjects) interact with the fog in order to make it volumetric.
+The High Definition Render Pipeline (HDRP) includes a volumetric lighting system that renders Volumetric Fog. HDRP also implements a unified lighting system, which means that all Scene components (such as [Lights](Light-Component.md), as well as opaque and transparent GameObjects) interact with the fog to make it volumetric.
 
 ## Enabling Volumetric Lighting
 
@@ -12,3 +12,6 @@ To toggle and customize Volumetric Lighting in an [HDRP Asset](HDRP-Asset.html):
 3. In the **Default Frame Settings** section, under the **Lighting** subsection, make sure you enable **Fog** and **Volumetric** if they are not already.
    ![](Images/VolumetricLighting2.png)
 4. If you want to enable reprojection support, check **Reprojection**. This option improves the lighting quality in the Scene by taking previous frames into account when calculating the lighting for the current frame. Currently, this option is not compatible with dynamic lights, so you may encounter ghosting artifacts behind moving Lights. Additionally, using high values for **Global Anisotropy** in the [Fog](Override-Fog.html) Volume override may cause flickering Shadows.
+
+## Notes
+Volumetric fog does not work for Cameras that use oblique projection matrices. If you want a Camera to render volumetric fog, do not assign an off-axis projection to it.