This section covers glow problems in the render.
Problem: Shader glow brightness changes during an animation, or Shader glow brightness is different at different rendering resolutions
The shader glow auto exposure is adjusting the overall brightness of the scene for each frame. When a glowing object enters or exits the frame, the glow intensity of all objects changes.
The shader glow auto exposure causes a similar problem when rendering at different resolutions. For example, shader glow brightness is different in a high resolution final render than in a low-resolution test render.
See ShaderGlow in Render > Multi-lister.
If you are also rendering at different resolutions, you must also scale these values based on the difference in resolutions (scale factor).
For example, if you are doubling the rendering resolution, the scale factor would be 2.
Alternatively, figure out the factor by which the *number* of pixels in the image increases, and multiply the glow by it.
Glow is missing from volume lights
Light from a volume light exists only within its volume. If the camera is not within this volume, then glow is not rendered.
Problem: Linear and area lights shine through objects, or Light glow shines through objects.
Linear and area lights do not attempt to detect if there are shadowing objects between the light and the eye. All other light types compute this occlusion factor.
See Hide Source in Render > Multi-lister.
See Opacity in Render > Multi-lister.
The radius of the light may be so large that it is never completely occluded by the object that should be shadowing it.
See Light Radius in Render > Multi-lister.
There is not enough memory for the renderer to calculate glows.
See Optimization.
See Hide Source in Render > Multi-lister.