In order for the HDRI files in your cubical maps to be used for lighting a scene there must be an "Environment" or "Simple Environment" Luminance applied to the Render Scene Luminance. This is where Image Based Lighting (IBL) comes from. The "Environment" or "Simple Environment" Luminance will sample the images assigned to a cubical map to obtain lighting information for your scene. The more sampling that takes place the higher quality and more accurate your results will be. The installed Luminance Presets let you decide what level of quality fits your needs.
There are three simple ways to apply a luminance to the Render Scene Luminance in TurboCAD. First, open or create a TurboCAD file that contains at least one 3D object with a material assigned to it. If you haven't already done so, install the Cubical Map and Luminance Presets that come with SOFTBOX (HDRI). Now use one of the following three methods to assign a luminance to the Render Scene Luminance of your file.
Bring up the Luminances Palette either by clicking it's tab or by selecting View → Luminances Palette... from the Main Menu. Navigate to the "SOFTBOX (HDRI)" category using the Category drop-down list. Right-Click on the luminance thumbnail labeled "Draft No Shadows". Choose Set Luminance from the context menu (figure 1). The "Draft No Shadows" luminance is now applied to the Render Scene Luminance.
figure 1 - Set Luminance
With the Luminances Palette still open and the SOFTBOX (HDRI) category visible, double-click one of the available preset thumbnails. The double-clicked item will be applied to the Render Scene Luminance.
From the Main Menu select Options → Render Scene Luminance... and TurboCAD will open the Drawing Setup window. If "Render Scene Luminance" is not already selected on the left, select it now. Choose the SOFTBOX (HDRI) category from the Category drop-down list and choose "Draft No Shadows" from the Luminance drop-down list (figure 2). Press the OK button and you're finished.