{When visualizing data in a realistically rendered 3D virtual environment, it is often important to represent not only the 3D scene but also overlaid information about additional, abstract data. These overlays must be usefully visible, i.e. be readable enough to convey the information they represent, but remain unobtrusive to avoid cluttering the view. We take a step toward establishing guidelines for designing such overlays by studying the relationship between three different patterns (filled, striped and dotted patterns), two pattern densities, the presence or not of a solid outline, two types of background (blank and with trees), and the opacity of the overlay. For each combination of factors, participants set the faintest and the strongest acceptable opacity values. Results from this first study suggest that i) ranges of acceptable opacities are around 20-70%, that ii) ranges can be extended by 5% by using an outline, and that iii) ranges shift based on features like pattern and density.

中文翻译：

---

3D 景观中透明叠加的不透明度范围研究

{在真实渲染的 3D 虚拟环境中可视化数据时，不仅要表示 3D 场景，还要表示有关附加抽象数据的叠加信息，这通常很重要。这些叠加层必须是有用的可见的，即具有足够的可读性以传达它们所代表的信息，但保持不显眼以避免使视图混乱。我们通过研究三种不同图案（填充图案、条纹图案和点状图案）、两种图案密度、实线轮廓的存在与否、两种类型的背景（空白和树木）之间的关系，朝着建立设计此类叠加的指导方针迈进了一步)，以及叠加层的不透明度。对于每个因素的组合，参与者设置最微弱和最强的可接受的不透明度值。