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Updated Dynamic Lighting

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Updated Dynamic Lighting (aka. UDL) is the new version of the Roll20 lightning system that is meant to replace Advanced Fog of War and Dynamic Lighting, combining them into a single, unified system. It features a stronger framework for future feature enhancements, is more performant, and has been updated for more current computing technologies. The old system is referred to as Legacy Dynamic Lighting (LDL).

In UDL, the old features of Advanced Fog of War have been renamed Explorer Mode to avoid confusion. Updated Dynamic Lighting uses WebGL, which is available in most computer systems and is supported by all the web browsers that Roll20 supports (Chrome and Firefox). The Legacy Dynamic Lighting has always used WebGL, so the change here is that Explorer Mode (previously Advanced Fog of War) now runs on the same system.

On January 14th, 2021, Roll20 announced Roll20-logo.png(Blog), saying that "Updated Dynamic Lighting has been in the works for some time, and we see the 1.0 Update not as a finish line, but a checkpoint.". Despite this, there exists still multiple known issues, such as performance issues, and visual glitches relating to Darkvision.

Roll20 have announced that LDL will be retired on soon Was May 18th 2021. More info:


Official Documentation

UDL was created after Roll20 had moved their Official documentation to the Help Center, so the Community Wiki doesn't have duplicates of these articles, so these features have better pages there:

Parallel Systems

Currently, UDL exist in parallel with the Legacy Dynamic Lighting(LDL).

While they continue development on Updated Dynamic Lighting and support for licensed products, both the Legacy system and the Updated will exist in parallel. However, when you switch from one to another, the revealed areas are not transferred over. So, for example, if you and your crew have been crawling through a dungeon with Advanced Fog of War on, and you decide to switch to the new Dynamic Lighting with Explorer Mode, your players won't see anything they had previously explored. Players can fix that by moving their tokens around to re-reveal the area.

Similarly, if you switch to Explorer Mode and then decide to hop back over to the Legacy system, anything you had revealed in the UDL system will be reset/hidden when changing to LDL. If you then switch back to the UDL, the revealed areas that you had revealed when you last used UDL(might?) still be there.

The Dynamic Lighting- layer, where you can add barriers that block light and movement, continues to function for both systems, and you do not need to change anything on that layer.

The Convert Lighting Tool making it possible to convert existing games to UDL automatically. This process can't be reversed easily, so if problems occur and you want to change everything back to LDL, you need to manually update all tokens & pages yourself. It's recommended to create a copy of your campaign, and perform the Conversion on the Copy, and keeping the original game as it is.


Breakdown of the main features.

Explorer Mode

Explorer Mode - reveal map as characters move around the map, and leave previously explored section greyed out.

With the Darkness Tool you can create patches of darkness that can be explorable, and it can also reset areas that have already been explored.

In LDL, the equivalent to Explorer Mode is AFoW.

Since April, you can also use Eclipses and freehand drawings for DL lines.

Dark Vision

In April 2021, Roll20-logo.png
& Alternate Senses where released, making it possible to use D&D5E-accurate dark vision, if you turn on "Nocturnal Vision". Total darkness will by default be shown in grayscale, but you can change the tint to have a color. E.g. Night Vision technology could give you a green tint, while magic-based darkvision might make sense to have a purple tint.

Darkness Tool

The Darkness Tool can be used for manage what players can or can't see, reset explored map back to darkness, or draw Permanent Darkness that even blocks normal vision.

It also incorporates features similar to the free Fog of War-tool, and replaces it's position on the Toolbar when UDL is active on a page. (FoW isn't compatible with UDL).

Convert Lighting

Convert Lighting is a one-way tool to automatically convert a campaign's Dynamic Lighting setting(tokens, pages) using LDL to use UDL.

You access it from your Game Management#Settings.


Main Page: Page Toolbar

Page DL settings for LDL and UDL are saved on separate tabs.




Main Page: Token Features

Token settings for LDL and UDL are saved on separate tabs.




There seems to be a lag between new UDL features and API getting access to them.

TokenMod(by The Aaron is a popular API that's been quickly updated when new UDL features have become API-accessible,

List of APIs using UDL-only features

Related API that utilize UDL to various degree:

Known Issues

The latest UDL Bug thread lists the , and this section (sporadically) updates based on it.

Known Issues List: (updated Feb 19th 2021)

Committed to fix before LDL Sunset:
  • PAGE REVEAL: This is an old problem that we believed to be fixed, but we have seen reports of it resurfacing. If you’re experiencing this issue, please let us know!
  • SETTINGS: There are reports of UDL settings not saving. We’ve released a patch that we believe solves this but will continue to monitor to see if it crops back up.
  • JAGGED LINES: Some usage of UDL can cause jagged lines on the fringes of token vision. We are currently working on an anti-aliasing solution.
  • LAG: We’ve heard you: Lag is the number 1 reason users aren’t converting to UDL. Since UDL started, we’ve put out a number of patches to improve performance; we are actively improving response times with each update. We’re currently testing a solution that will significantly improve network performance that we will be rolling out in the next couple of weeks.
  • NIGHT VISION: There are parts of Night Vision that still need to be fixed, like Night Vision tokens overlapping and animated tokens having a ghost like effect on the GM layer.

Issues that might not get fixed before sunset:

We also have a few issues that we’re still collecting info on. While these bugs are high priority, we’re still investigating the best way to fix them. If you are experiencing any of these, please report it in our bug forum. The following is a list of fixes that will be addressed either before sunsetting LDL or sometime soon after:

  • RING/BULLSEYE EFFECT: There is a documented issue where some light sources have a ring/bullseye effect to them.
  • PAGE FREEZING: There have been a handful of reports of UDL freezing games. We’re currently determining the root cause of these freezes. This is the bug we currently need the most information on. If you’ve experienced it, please let us know through our Help Center.
  • GRID: We’ve received reports of Players and GMs losing sight of the grid when using characters with Night Vision.
  • VISIBILITY: We’ve received reports of Players and GMs losing their sight, or experiencing tokens disappearing after moving specific tokens.

Fixed issues/past threads:


  •  ?? – First public info on UDL
  • March, 2020 – UDL was made available to Pro members on the Dev Server.
  • April 8th, 2020 – UDL was released as opt-in feature for Pro/Plus users, after having been available over a month on the Dev Server for Pro subs to try out.
  • July 30th, 2020 – Roll20 announced UDL to have reached Feature Parity with LDL, but still have issues and optimization to do.
  • August - December 2020 – regular updates & fixes where applied to UDL, and these minor change where communicated mostly in the UDL megathread and possibly twitter
    • There where no Blog Post or larger announcements during the time for UDL. On the monthly Community Roundtables(Twitch), questions about UDL progress was answered, and possibly some minor changes where mentioned.
    • During Roll20Con 2020, some updates where highlighted
  • January 14th, 2021 – Roll20 announced
    • "Updated Dynamic Lighting has been in the works for some time, and we see the 1.0 Update not as a finish line, but a checkpoint.". Despite this, there exists still multiple known issues, such as performance issues, and visual glitches relating to Darkvision.
    • With the Update 1.0, they also emphasized that "We will still support Legacy Lighting for a while, but we feel it’s only fair to let you know that we will be deprecating our support for the Legacy system sometime in the future. "
    • No timeline for phased out LDL was announced.
    • Roll20 would close the current UDL feedback thread shortly and start a new one for Update 1.0
  • Jan 27th, new feedback tread opened for Update 1.0: (Jan 27th, 2021)
  • Feb 17th 2021, it was announced that LDL will be Roll20-logo.png(Blog)
    • Feb 6-17th, several updates related low light/dim light was rolled out. Adding a dim light opacity slider, setting in "Default Settings", and fixes.
    • Feb 18th,


APIs have access to most UDL features, and some APIs such as TokenMod have updated to support UDL as best as it can.

There are some API, such as , which only works with UDL, and not LDL.

Check API:Script_Index#Dynamic_Lighting for list of some API that interacts with UDL & LDL.

Related Pages

See Also

Blog Posts