Indoors1

This demo models an indoor scene that contains a point source near the ceiling and a simple cut-out "window" (no glass) and cut-out doorways. The camera is placed inside the simple kitchen room. Interior illumination is provided primarily by a point source for the default simulation, but can be turned off to show the effects of low-level scattered diffuse light.

The camera is placed inside a "box-like" kitchen with some simple objects and materials. Interior illumination is provided by a point source near the ceiling and a cut-out window and doors.

For more information on configuring sources, consult the User-Defined Sources Manual and the other Sources1 demo.

With the point source enabled, the signal in the room is dominated by direct scattering of the source towards the camera. With it off, the only source of illumination is the sky-light outdoors that enters through the windows/doors and scatters around the scene.

For the atmosphere, we simply use the uniform atmosphere model with a very low irradiance and no direct components.

The geometry of the scene includes the kitchen (see geometry/kitchen.obj) and the point source in the kitchen (see geometry/1ptsource.gdb). The source is combined and positioned in the room in geometry/scene.glist.

To turn off the light source, switch the "true" value in the enabled attribute of the source object entry to "false" and re-compile the scene (there are ways to enable/disable sources—and objects in general—without recompiling the HDF, but that is beyond the scope of this demo).

These demos are intended to be run from the command line using DIRSIG5 using the jsim format. The specific runtime options and post-processing listed below.

The images were made using the RGB channels of the output and the gamma scaling option of the envitopnm tool (gamma=2). The first image was made using the scene with the point source enabled, and to highlight the impact of direct illumination, the maximum number of bounces was restricted to one ("--max_nodes=1"). The convergence criteria has been carefully set to capture low signals, but to do so adaptively: "--convergence=30,500,1e-12". Note that because we have limited the amount of scattering, areas that are not directly illuminated by either the sky or the point source will be perfectly black.

For the diffuse simulation (source disabled), the amount of scattering allowed should be fairly high (at least the default number of nodes per path). Also, because the signals are so low and over a large dynmic range (i.e. between directly viewing the sky through the window/door and seeing the scattered sky light indoors), it is convenient to fix the convergence to a specific number of paths per pixel ("--convergence=500,500,0") was used for the image shown.