[sldev] Optimus Prim vs. Megatrim: "The Big Prim Problem"
Argent Stonecutter
secret.argent at gmail.com
Wed Oct 17 09:06:53 PDT 2007
On 17-Oct-2007, at 09:15, Dzonatas wrote:
> What to do with the megaprims?
Keep them, let people create and rez new megaprims up to 256 meters,
don't make it a complex operation to do so, don't magically convert
prims into linksets, just ignore them in the physics engine.
Have an option on the editor or debug menu, "allow prims over 10
meters".
When you make a prim larger, you get a warning.
When you rez a prim larger than 10 meters, it gets ignored by the
physics engine.
This need not be exactly the same as making it phantom: there
shouldn't be any need to make a whole linkset phantom because one
prim in the linkset is a megaprim. The physics engine would simply
ignore that prim when generating its approximation of the linkset.
The whole business of automatically generating sets of new prims that
behave like a single prim seems unworkable to me. The shape of a
component prim that results from resizing a truncated skewed twisted
profile-cut torus is just too complex to describe compactly... the
server and the client both will have to completely ignore the
component prims, and perform all the same calculations for rendering
and physics as if it was a single megaprim, and in addition generate
magic linksets. Where are the savings?
For structural pieces? Just embed transparent non-phantom prims
inside the megaprim. For objects of any significant size, the
difference between a section of a sphere and a plane are less than
can be represented by the 10cm resolution of the physics system
anyway, and besides the physics engine routinely generates bigger
errors than that in the approximations it uses for even 10m
objects... try walking on a 10m twisted cube sometime: you often
float over the surface or sink into it. You can do better positioning
a prim framework by eye... and almost certainly use fewer total prims
than you would creating a single set of prims that looked like the
same megaprim, because you know where it matters that a floor is
"real" and where it doesn't.
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