TAPESTRY: The Art of Representation and Abstraction
Shadows
In form•Z you need to be aware of three controls which affect the casting of shadows.
Algorithmic Options
Some rendering algorithms simply cannot manage shadow casting (such as wire-frame). Others may only cast shadows as an option, often OFF by default. You need to make sure that the algorithm you wish to use is capable of casting shadows and that this feature is activated.
Light Source Attributes
It is not uncommon to include light sources in models for atmospheric effects or to simulate a diffuse interreflection. While the light from such sources is desirable, it might not be desirable for the light to cast shadows. For this reason, each light source has a "shadow casting" control.
Geometry Attributes
The ground-form for an architectural model may contain many polygons, but it will almost never cast a shadow on itself or on the building. Similarly, adjacent buildings in the site model might cast shadows on the site, but we might never care to see shadows cast upon those buildings. These situations help understand how we might use the "Casts shadows" and "Receives shadows" geometry attributes while composing a rendering.
For a shadow to be cast the algorithm must be actively processing shadow data, the light source must be casting shadows, the geometry originating the shadow must be casting shadows, the geometry on which the shadow falls must be receiving shadows, and the geometry of the light source, shadow source, and shadow target must be correct to create the shadow. That is, if you stick a flag-pole in the ground, set everything right, but light it from below, don't be surprised if there's no visible shadow! Phew!
form•Z Shadow Controls
| Type of Control | Required Action |
|---|---|
| Algorithmic Options | Select Display > Display options or option-pick the rendering algorithm you wish to test (such as Quickpaint) in the Display menu. Make sure that the "Render with shadows" option is selected. If you don't see a checkbox that algorithm doesn't do shadows. |
| Light Source Attributes | check the "Options > Lights > Edit ..." dialog box (Options menu, etc.) and make sure the appropriate light sources cast shadows. |
| Geometry Attributes | Make sure the geometry is casting shadows. This is controlled by the "attributes" tear-off tool palette, and you can use the "query" tool to view the attributes of any portion of your data, and to edit it. |
Last updated: April, 2014
