The Shadow Options panel sits within the 3D Model Window and is used to control the display of shadows on the window. You can open and/or close this panel by clicking in its title area. If you click on the status icon on the right-hand side, the panel will open/close without affecting any of the other panels around it.
The top three checkboxes control what surfaces shadows are actually drawn on within the 3D model. You can uncheck any of the boxes to focus in on a particular shadow effect.
Daily Sun Path
Displays the sun-path for the current day as a dotted line running across the model. When this is displayed, you can click and drag the sun with the left mouse button. Hold down the Control key to update the shadow display in real time. You can also use the Shift key to interactively change the current date as you drag.
Annual Sun Path
Displays the path of the sun through the sky for the first day of each month of the year. The first six months (Jan-Jun) are shown as solid blue whilst the second six months (Jul-Dec) are shown as a dotted line. Each hour of the day is shown as a figure-8 due to the analemma effect.
View From Sun Pos
When clicked, the 3D model display changes to show the model from the perspective of the Sun. As the Sun is so far away, its rays are all but parallel. Thus, the model is shown without any perspective distortion and from the current azimuth and altitude of the Sun. To reset back to a perspective view, uncheck the box or drag the view with the right mouse button.
The items in this section control shading effects in the model, in which the colour of lines and surfaces are moderated by the angle between their surface normal and the current Sun position. This slider controls the contrast between shaded and unshaded surfaces. Even though shading effects may not be currently displayed (see below), the setting of this slider will also affect the contrast of shadows drawn in the model.
Check this option to render each surface with a colour determined by the angle of incidence of light from the Sun. This produces slightly more realistic renderings by allowing you to distinguish between surfaces in direct Sun and those in shade.
The controls in this section allow you to animate the display of shadows in the model display. The slider bar controls the speed of the animation. The buttons immediately below animates through the hours of the day or the days of the year.
This can be used in conjunction with any of the other display options. For example, it works particularly well with the View From Sun option, allowing you to clearly visualise when objects are shaded or exposed.