This is an ongoing series intended to help Second Life users, indeed all metaverse citizens, better understand some of the inner workings and underpinnings of their viewers, the connection to the servers and the servers themselves.
Today I will talk about draw distance, how it helps, and how it can hurt.
Draw distance is the range of view from your camera’s position. A distance of 64 meters means exactly that, the farthest your can see is 64 meters. And the way prims work in virtual worlds, as long as the center of the prim is in view then the entire prim is in view, regardless of the distance to its farthest point.
Your draw distance setting does more than just define how far in front of your camera you can see, because what you see, or your field of view, is actually a cone of about 60 degrees, so it includes everything inside that cone. What’s more, it defines an entire area around you, or a sphere. And the greater your draw distance, the greater the sphere. And the bigger the sphere, the more you cause your viewer to render.
Most viewers will try to discard objects and/or textures that are outside your field of view, but that still leaves a huge spatial cone, in which everything contained must be rendered. And if you move your field of view then the viewer has to render all the new stuff and discard all the things you no longer see, so there’s memory management overhead.
Just to give you an idea of the amount of rendering your viewer must do, here is the equation:
V is the volume of the sphere, π is the constant pi (about 3.14), and r is the radius, or draw distance. Setting draw distance to 32, the lowest one can set in Preferences, the volume of the sphere is over 137 thousand cubic meters. Granted there aren’t prims in every single cubic meter, but the potential is there.
Now let’s double the draw distance, 64 meters. The volume of that bigger sphere is almost 1.1 million. Actually, eight times the volume. Eight times the rendering demand. Double your draw distance again to 128 meters and your volume become almost 8.8 million cubic meters. Eight times again, or sixty four times the rendering demand as that for a draw distance of only 32 meters.
What are some reasonable draw distances? Well, those depend on what you’re doing. If you’re building, for example, and your build is rather small, set your draw distance to something just a little further than the furthest prim in the build. If you’re working on jewelry then obviously a draw distance of 32 would be plenty.
If you are in charge of some event, perhaps a host who must greet anyone within shout range, then a draw distance of 100 or slightly more would be appropriate, but only for the duration of the event, then drop it back down.
And, something else to consider: if your computer only meets minimum specifications, it may not be powerful enough to support a large draw distance. Keep that in mind if you find yourself needing a huge draw distance but crashing frequently.
If you use a viewer that allows greater control over draw distance, such as Firestorm, there are a couple benefits to that. First, you can set your draw distance to a much smaller value, say 2 or 4, when working on jewelry. But also, if you have problems with your visible cache, and your normal solution is to sit on one of those visible cache rockets, you don’t need to; set your draw distance to zero, wait five or so seconds and then set it back to the distance you desire.