Real-Time Site Analysis

I often find myself trying to explain the concept of shading masks - typically over the phone which is never easy. Thus I thought I'd try both demonstrating and illustrating the basic ideas in an interactive web app. In the end it turned out far better than I ever thought it would as I managed to get the required ray-tracing working in pretty much real-time. The aim is that, as you interactively manipulate the 3D model or drag the position of the dome around, you can see instantly the resulting overshadowing effects at the dome centre, thus better understanding their relationship.

Blog Details

Site Analysis Applet: A tool for dynamically examining overshadowing within a complex site. You can interactively drag the point of interest (the center of the hemisphere) around the site and the overshadowing will update. You can also manipulate and reshape the surrounding obstructions which will also update the overshadowing in real-time. Use the middle and right buttons to pan and rotate the view respectively.

Real-Time Site Analysis Applet

The above is an embedded interactive Java applet that demonstrates the overshadowing of a point within an obstructed building site. The aim of the tool is to provide dynamic visual feedback on the degree of overshadowing of the point at the centre of the shaded hemisphere. The shaded hemisphere itself is just a visual construct onto which the calculated overshadowing is projected so that you can see it within the context of the model.

Changing the Point of Interest Position

Click the point at the centre of the hemisphere to select it, and then you can interactively drag the hemisphere around the site. As you do, the new overshadowing is ray-traced and projected onto it in real-time. This allows you to very quickly gain a good intuitive understanding of the effect of each obstruction on the degree of shading as you move closer and then further away.

Changing the Obstructions

You can also click on any surface of the surrounding obstructions and, once the drag arrow is shown at it’s centre, click and drag that to change the shape and size of each obstruction, including their height. You can toggle between Surface and Object modes if you wish to edit just the surface itself or the entire object.

Visualising Rays and Colour-Coded Shading

There are some interesting visualisations hidden in the tool so it’s worth playing with the four large horizontal buttons along the top and the very top set of three vertical buttons running down the left side. These allow you to match the shadow colour with the colour of each obstruction so that you can more clearly see the relationship btween the two. You can also visualise the actual rays being used to calculate the overshadowing and then actually animate them to see teir impact. Another option is to map an example of annual incident solar radiation over the hemisphere and use the shading to show where that is reduced. This is a simple proof of concept at this stage so you can’t change the location or weather data.

Conclusion

Again, I’ve used up all my time coding and later today is my first day back at work - so a detailed explanation of how to use it or how it works will have to wait for another day. However, hopefully it’s pretty self explanatory and worth playing around a bit with…

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