Ray Tracing

Progress Dialog

A new option in the View|Preferences|View Options dialog provides control over the ray increment used to update the ray number displayed in the Ray Progress dialog. Increasing the number can increase the raytrace speed by reducing the number of updates sent to the dialog box and times the dialog is queried to see if the Cancel button has been pressed.

Ray Tracing modes

TracePro allows you to select different modes for storing rays during the raytrace. These are selected by checking one of the checkable items at the bottom of the

Raytrace menu. You can choose either Analysis Mode or Simulation Mode. This allows you to trade off the amount of information that is available versus the amount of memory that is consumed. Analysis Mode generates more ray data but consumes more memory, while Simulation Mode generates less data and consumes less memory. To activate one or the other of the choices, simply check one of the items before beginning the raytrace. If you choose Simulation Mode, you will have to specify an exit surface before the raytrace starts if you wish to see an irradiance map after the raytrace is completed. TracePro will not allow the raytrace to be done and will warn the user if an exit surface has not been specified

Analysis Mode

In an Analysis Mode raytrace, TracePro saves all of the ray data that is generated during the raytrace. This allows you to view the irradiance on any surface in the model after the raytrace is completed. To do this requires a large amount of memory. The more ray splitting that takes place for each ray and the more surface intercepts that rays undergo before they are terminated, the more memory is required for each starting ray. A raytrace started with many rays (tens or hundreds of thousands or more) and with many ray-surface intercepts for each ray can require hundreds of megabytes of memory.

TracePro allocates memory as needed during the raytrace by requesting memory from Windows. Initially, your physical RAM will be used. If all the physical memory is used, the operating system will allocate memory from virtual memory. Virtual memory is disk space that is used like physical memory. Accessing virtual memory is much slower than accessing physical memory, so if TracePro is doing a raytrace that requires a large amount of memory, the progress of the raytrace will slow as it begins to use virtual memory. If all available virtual memory is used up, TracePro will discontinue the raytrace. You can increase the amount of virtual memory available from the Windows Control Panel, as your available disk space permits. On a Windows NT computer, you must be logged in with Administrative privileges in order to do this. From the Windows Task bar, select Start|Settings|Control Panel and double-click on System. Select the Performance tab and press the Change… button in the Virtual Memory area. A dialog box will open that allows you to change the virtual memory settings. If you are not comfortable doing this yourself, you should seek the help of a system administrator or other expert.

You can increase the amount of physical memory by installing more RAM in your computer. Windows limits the memory space an application can access to 2 GB.

To perform an analysis mode raytrace, select the Analysis Mode item at the bottom of the Raytrace menu. If there is a √ next to the Analysis Mode item,