[Uni-verse] Report on UVAS 2007-04-11

[Peter Lundén]

The perceptual simulation is now implemented in UVAS.
The implementation is based on the Sabine equation and a simple
parametric model of room acoustics.

A room has size and shape and a default absoption (10 bands), solving
the Sabine equation gives the reverbration time. A model shoebox room is
build and the early reflections are traced in that room.

The parameters are stored in the floor, to find the right parameter set
a ray is casted from the listener downwards, the first surface that is
hit is consider as the floor and the parameters is then extracted from
that surface.

In verse the parameters for a "room" are stored in a tagged text node.
The text node is linked in a similar way as multimaterials are handled,
via a layer named "room" in the geometry and then linking the text node
from the object node using the same target as found in the geometry
layer,the link is named "room".

Two tasks that remains to do is better culling of the sound sources, in
the current version only disrtance is considered. The geometry should
also be taken into consideration, that will be fixed later when the
geometry handling is in better shape. The second task is that more
parameters should be implemented, now only room size and shape is
implemented, also livelyness  and "sharpness" (both manipulating the
absorption) should be implemented. The math for this is done so it is a
very simple task and it will be done during a sutable coffee brake.

The verse interface need more testing, I do not yet have more complex
verse data to test on, just a simple cube. The mechanisms used are very
similar to material handling and share most of the code with that so I
dont think there will be any major problems.

The new version is developed in ist own branch in SVN and will be merged
with the main branch later today.

--PLu