Abstract: An authoring system provides a realistic rendering that may be updated and displayed continuously while simultaneously allowing full access to all authoring tools. The system is an enhancement to an authoring environment for 3D modeling. The rendering is incorporated in the authoring environment in a way that avoids conflicting with the abstract images and tools useful for working with 3D models such as would obtain in a WYSIWYG implementation. The computational burden of rendering is handled by rendering in an asynchronous parallel thread with respect to that supporting the authoring UI. The number of pixels that must be ray-traced is reduced by several mechanisms including: limiting the number of objects, limiting the resolution of the display, tailoring the size of the field-of-view window (while providing orientation context by placing the rendering on top of a wire-frame view). Also, only portions of the scene that are affected in a visible way by updates are re-rendered.