Why and what is the Cool VL Viewer ?

The "Cool VL Viewer"(*) (formerly known as "Cool SL Viewer" which first public release was v1.18.4.3, released on 2007-11-16) is a third-party viewer for Second Life® and OpenSim grids. In the name, "VL" of course stands for virtual life.

The exact reasons behind the creation of the Cool VL Viewer can be found in this message on the forum, but fact is that Linden Lab® (hereafter referred as by "LL") just cannot happen to take into account in a timely manner all the patches and bug fixes which the open source community provides. You can publish a patch and see it actually taken into account only months later... when at all !

Plus, LL often implements changes in their viewer without any or with very little regard to what their customers, the "residents" do like or not; the worst of all these changes in regard to the UI were probably the Voice viewers v1.18.2 chatterbox (and they did it again in v3 viewer's "Flexible UI", with the cumbersome and right out monstruous "Conversations" floater), or the sidebar in their v2.0 viewer UI. Such changes are considered by many users as true regressions, either in usability or functionality, and usually both.

As a response to the problems cited above, the Cool VL Viewer puts emphasis on high UI coherency from one version to the other (meaning no bad surprise for "old timers") while staying in sync with Linden Lab's official viewer features, high stability and reliability, and a high reactivity to new patches and bug fixes provided by the Open Source community. The Cool VL Viewer is also kept fully OpenSim-compatible.

(*) Please, get the name right when citing it elsewhere: the name is "Cool VL Viewer" (yes, "Viewer" is part of the name, just like "Tower" in "Eiffel Tower"), and not "Cool VL", "Cool Viewer", etc...

Who is maintaining this viewer ?

Henri Beauchamp (SL avatar name), creator of the "Cool Products" in SL.

For announcements and support, please see the Cool VL Viewer forum.

Why would I use your viewer ?  What can I expect from it ?

Using this viewer or not is entirely up to you, of course. But it got quite a few bugs and regressions fixed, as well as really Cool new features. ...

The code changes used in this viewer have been either produced or reviewed and tested by me (and I have been programming for over 4 decades now... Not a script kiddy). This viewer is the one I use everyday, and should a patch introduce any regression, it would be either corrected or removed.

Such things as the actual usefulness of a new feature comes into consideration before implementing it. I try to stick the closest possible to LL's official viewer and only patch the bugs and regressions, sprinkling the mix with some, really useful features (such things I could not myself "live" without anymore after having tried them).

To cope with more "exotic" and very specific features that would just bloat the code uselessly and complexify the UI for most users, while being only of real use for a small number of people, I also implemented viewer-side Lua scripting, which makes it possible for anyone with minimal scripting ability to customize the viewer for their need. This also makes this viewer a good candidate for automation and bot creation.

This viewer also implements the RestrainedLove (formerly known as "RestrainedLife") features: these features are disabled by default, so you won't notice any difference with a "normal" viewer till you enable them manually.

To enable or disable the new features of the Cool VL Viewer, you simply open the "Preferences" menu (which has been largely expanded and contains many new settings when compared with LL's viewers); be sure to read the tool tips for each setting (they are worth a full documentation).

Please note that since LL published a Third-Party Viewers (TPV) policy, in order to use this viewer to connect to Second Life, you must first read and agree with these terms (which will be presented to you on the first run of the Cool VL Viewer).
The Cool VL Viewer is itself TPV-policy compliant and listed in SL's official Third-Party Viewers Directory (TPVD).

What operating systems and what hardware are supported ?

You will find Linux x86_64, Linux aarch64 and Windows x86_64 builds on this site. Links to macOS x86_64 builds can be found in the Latest macOS releases section of the forum (they have been built by Hyang Zhao, Guru Coyote and Kathrine Jansma in the past, and Catten Carter is now providing builds: thanks and kudos must go to them for their contribution); instructions are given in the sources tree for building the viewer yourself with Xcode 12 or 13.

The provided Linux x86_64 builds should run on any Linux x86_64 (2020-ish or newer) system with glibc v2.28, libstdc++ v6.0.25 and glib v2.58.3 or newer. The Linux aarch64 builds require glibc v2.35 or newer. You may as well easily build the viewer yourself (with just one command !) on any x86_64 or aarch64 Linux system.

The provided Windows viewer binary should run on any Windows x86_64 system, from Windows 7 upwards. However, the web plugin no longer runs on anything older than Windows 10 (this is a limitation due to Chromium requirements).

As for the hardware, you will obviously need an x86_64 (or aarch64, for Linux ARM64 builds) CPU to run the provided builds (the better the mono-core performances of the CPU, the faster the viewer will be). SSE3 support is also now required for x86_64 builds (because of Chromium requirements again).
The supported (i)GPUs are OpenGL v2.1-capable and better ones, with NVIDIA (preferred, since it got way faster OpenGL drivers), AMD or Intel GPUs, but OpenGL v3.1+ capable hardware is highly recommended (and needed to enable the PBR rendering mode). Intel iGPUs and AMD APUs are known to be too slow, most of the time, but may still run the viewer.
For the memory, 8GB of RAM is nowadays a minimum, with 16GB highly recommended, and 32GB for a comfortable experience (you may thank the creators of the million-polys meshes, the 1024x1024 material textures (3 textures per face for ALM, and now up to 4 for PBR), and in general the poor design of most products uploaded in SL).

OK, where are the files ?

Please, see the Linux installation HOWTO (and its ARM64 flavour) or the Windows installation HOWTO for the details on how to install the viewer.

SHA1SUMs (*) for the current releases:

d3c589254ce31fb18cfb49374642ef53925c9a73  CoolVLViewer-
67ca2c187c288999ace11f1cc79567fc604e261f  CoolVLViewer-
5fc4439c6fd7e3d063252d8164183e8ba2bcd5d9  CoolVLViewer-arm64-
cb3bf0eb57887ec7deb745670bd709cb7bf1ce39  CoolVLViewer-src-132010.tar.bz2

Linux users may use the 'sha1sum' command from a terminal, or utilities such as gtkhash. Windows users may use any of the programs available to them; I'd personally recommend the HashCheck Shell Extension which is free, Open Source, integrates with the explorer (adding a "Checksums" tab to the file properties dialog), and works on all Windows versions from 7 to 11.