Avatar Rendering Cost
Avatar Rendering Cost (ARC) shows a point score above each avatar's head which indicates how "laggy" they are on the viewer-side. ARC is found in Advanced Menu > Rendering > Info Displays > Avatar Rendering Cost. The score is a factor of the size and number of textures used, and the number and type of primitives used. Avatars with large textures, lots of flexi-prim parts and high prim count objects, and/or invisible parts will score higher than one that uses fewer/smaller textures, using a few sculpties instead of many basic primitives, etc.
The score are color coded. The center of the Yellow band is about a score of 1,000. The numbers turn fully red at 2,000. It's generally best to be considerate of others when putting together your avatar, and to do what you can to stay under a score of 2,000, especially in crowded areas. Under 1,000 is even better. These are only guidelines, but be aware that the higher your score is, the more lag you generate for other Residents, particularly those with older machines.
ARC is somewhat controversial - there are people who have made a game of creating high ARC avatars that don't produce much lag. However, if you keep in mind that it's an estimate, it can be a useful tool.
Lowering your rendering cost
Most people can make an avatar which looks similar to their normal avatar, but has a lower ARC. It can be a good idea to keep a low-ARC avatar to take to high-lag or popular events, or to wear to classes that are likely to generate lag (such as building or scripting classes).
- Start by bringing the ARC up: Advanced Menu > Rendering > Info Displays > Avatar Rendering Cost
- Make a note of all the attachments you wear on your regular avatar.
- Detach everything. (Right click on yourself, select Detach, then select Detach All.)
- Gradually attach each item, making a note of which items increase your ARC most.
- If you're a competent builder yourself, look at "How ARC is calculated" and remove unnecessary particles, flexi, bumpmapping, texture animation and prims from copy/modify high-ARC objects.
Some hairstyles, for instance, have more than one style within the same object, with the second style being invisible. You can reduce the ARC of that hair just by making a version without the second style - and look exactly the same.
- Otherwise, you can look for low ARC objects that have a similar look to the high ARC version. Use demos to figure out the ARC of an object before purchase.
What to do if someone with high rendering cost is causing you lag
If you have avatar impostors enabled, mute them. They will be replaced by an imposter, with the effective rendering cost of 1. Their original rendering cost will still be displayed. This is particularly useful on machines that get poor framerates, you can mute high cost avatars to help increase your framerate in crowded areas.
How ARC is calculated
- An avatar with no attachments has a score of 1.
- You can have the fanciest possible Linden (aka mesh) clothing, hair, and shoes, and still have a score of 1.
- 10 points for each prim.
- This is a base cost for the prim, other points add to this cost.
- 5 points for each unique texture (on prims).
- Coloured but untextured prims don't add ARC for textures.
- Textures used to make clothing, hair, shoes, etc don't add ARC.
- Each texture counts once, so hair that has fifty prims but only one texture across all the hair adds only 5 points for textures. (Note that most hair has at least two textures, one with transparency to make the 'ends', and one without for the main bulk of the hair. So hair like that adds 10 points for textures.)
- 1 point for each invisiprim.
- This isn't transparency, but the invisiprim texture used for blocking avatar skin. Its most frequent use is prim heels, it's also often used for furry or tiny avatars.
- 1 point for each prim with glow.
- 1 point for each prim with shininess.
- 1 point for each face of every prim that's planar-mapped.
- 1 point per metre, per axis, for each prim.
- This most often affects skirts, capes, long hair, large wings and long tails.
- 4 points for each prim with bump mapping.
- 4 points for each prim face with transparency.
- Note that this is per face, not per prim.
- This includes partial transparency, like 'endy' hair.
- It also includes prims which don't seem to have invisibility, but do - if it shows up as red when you turn 'highlight transparent' on (under the view menu), it counts.
- 4 points for each prim face with an animated texture.
- Note that this is per face, not per prim.
- 8 points for each prim that's flexible.
- 16 points for each prim that emits particles.
- The most common use of particle emitters is bling.