VisGroups determine when a particular object is shown or not shown in certain circumstances. They are made up of combination of power of 2 values. So you can have the first, second and third visgroups enabled by 1 + 2 + 4.
These values are assigned to an object through the SCN file with Visgroups=(7) for example.
In the 3ds Max plugins and Scene Viewer they are signified by a character.
This section details what the different details signify.
In VIS group A includes the least important objects on the track. These are objects that can be removed because they are not important and can reduce the poly and texture counts. These are usually more minor details which add to the view, but removing them doesn't reduce the graphic detail too much.
Remember everything in A is turned off as well. Vis Group B includes a selection of objects that are high poly counts and are more visible as you drive than those removed in group A.
Remember that everything in A and B are turned off as well. This VIS group removes all the remaining items that we wish to cull to keep performance up at the lowest settings.
The next two VIS groups are a bit complicated but are there if you have the time to use them.
This is setup so that when a user selects Low detail D will automatically be turned off and replaced with E. If nothing is tagged with either, nothing will change. It will then work just as above A-C.
This group is applied to the majority of objects which are not key to the rear view mirror. This generally just means the main track ribbon, barriers, fences and key buildings. And perhaps some trees walls to keep the environment looking believable in the mirrors.
This group is generally removed to keep the race track looking less busy or in non race mode. This means less people in the grandstands, parked vehicles etc.
Use this to remove some of the people and perhaps the objects that you only want to appear in Practice mode.
Not much will be removed from the race session. If you have any objects that are just for Practice or Qual mode than this is the tag for them.
This is used to specify objects that will only appear during day time. This can be useful for swapping out objects for simpler geometry at night for example.
Object that only appear at night, perhaps some emmisive building glows or distant street lights can be added this way.
For example there maybe extra detail outside the track ribbon we wish to be visible when only using external cameras. Such as doubling up the number of spectators / parked vehicles, or just areas that just aren't visible when driving.
Similar to the other, just incase there are some objects we don't wish to be visible in a warmup session.
Instance=GrandstandC_01{ VisGroups=(32) MeshFile=GrandstandC_01.gmt CollTarget=False HATTarget=False ShadowCaster=(Static, Texture) ShadowGroups=(12) }
Beneath are some objects that we usually assign various visgroup settings.
Pitlane Props (Small)
Barriers / Fences (Medium Distance)
Live TV Screens (just the mesh that shows the screen buffer) - Only if the rest of the object is always rendered.