Site Sun Study

[Stress Co_]

This is a bit hard to explain, but I'm looking for a simple way to model the "surveyed" horizon line (skyline) of a site, in order to run a more accurate sun study (i.e., has the sun set behind the mountain ridge or the building next door).

I built a cylindrical "mask" which follows the elevation of the skyline (from a site survey that graphs the angle and bering of the skyline). The elevation varies depending on the radius of the mask, but it's easy to figure out.

The best solution I've found is to use the mesh tool. Any better ideas?

Would it be difficult to create a GDL cylinder with nodes every 5 degrees, where one could dictate the elevation of each node?

Just wondering.
Marc

[Rick Thompson]

I can't help you any, but it is interesting to me as I was just emailing back and forth with someone who builds tools for sun studies. I need something for my web site (new version not online yet) so people can make basic determinations for shadows on passive solar houses. He has some very nice tools already. He as asking me if I thought many other designers beside me might have an interest. So, interesting timing:)

His web site is http://susdesign.com/tools.php and there is a sun angle tool, and others that might be helpful.

[Karl Ottenstein]

Hi Marc,

I import that actual terrain of interest from Google Earth. It is low polycount and not extremely accurate, but it can give reasonable sun results (because it is the close to the right size, and in the proper spatial position), and nice view-study possibilities when it is properly texture mapped (from Google) so that you can show the client what they will see out of their windows.

But...for some reason, I got somewhat poor and slow shadow results from Lightworks in AC ... but reasonably decent in Artlantis.

In case that helps.

Cheers,
Karl

[Anonymous]

Karl, I wasn't aware that you can import the terrain from Google Earth... I have used it to place site overlays, but that is it. I have just now looked through the Help guide for Google Earth, but can't find any documentation on how to import the terrain... Am I missing something obvious here? The Pro version perhaps?

Thanks!
John

[Stress Co_]

Thanks Karl and ditto what John said.

[Karl Ottenstein]

I need to write up an article on the wiki about it (but am locked out at the moment), or maybe a chapter in a book. 😉

But, there are a couple of ways.

On PC, the Google Earth Connection lets you capture terrain. For a small area, this is fine, as it is built-in and convenient. But, for a large area - the three of us are in the mountains and need larger areas - I'm not happy with it because each bit of terrain is a new object and you have to make sure that you never move them out of their original positions.

On Mac and PC, SketchUp has a function to capture whatever terrain is shown in Google Earth. You can only zoom out so far and then capture is now allowed. Takes a couple of times to figure out the right zoom level. Each capture ADDS more terrain to your SketchUp model. You have to learn to overlap just enough to get continuous terrain, but not so much that you're adding unnecessary repetition.

The terrain grabbed by SketchUp (free download) gets a grayscale image map for some odd reason. So, before I move my position in Google Earth, I File > Save Image a color image of what was just captured. (I edit the image in photoshop later to brighten it up/etc and replace the image in my 3ds texture folder with the color one to end up with colored terrain.)

Once the SketchUp model looks decent, we're back to the Mac vs PC problem. On Mac, you have to have SketchUp Pro (the paid version) to be able to export the terrain as 3DS and then import it into ArchiCAD using the 3DS import 'goodie', resulting in a single object. On PC, if the Google Earth Connection add-on is installed, you can open the skp file from free SketchUp to convert the terrain to an AC object. A bit more futzing to get the color images to replace the grayscale ones for the textures then.

Finally, to locate the terrain relative to the building site, it is just an issue of repositioning the terrain roughly in 2D and then fine-tune in 3D. It requires that part of the terrain is your building site and that you have a modeled mesh/topo/boundaries or something that you can map to identifiable imagery from Google Earth.

Note: the terrain does not have to be contiguous! In SketchUp/Google Earth, you can grab your building site (for alignment) and then grab some mountain peak area to the north, one to the west, etc - all floating in space, basically, but providing the things that you want for determining your views. For sun studies, of course, you'll need to go continuous, so for Marc's illustration, the capture would look like a doughnut with the building site isolated in the middle somewhere.

Cheers,
Karl

[Anonymous]

Karl,

Thanks for the chapter!! I really appreciate the advice. And what do you know, a PC is finally good for something! Do you have any decent snow there? If so, send some our way.

Marc, just noticed that we're neighbors.. Maybe we should head to Bozeman to ski?

John

[Karl Ottenstein]

You're welcome. Not a great snow year, but at least there is some! Come on up!

Attached is a zoomed out image from Artlantis of a site in Jackson, WY on a winter morning (as far as the sun is concerned - that green grass is just playing games with your mind!) The building site is at the lower red arrow.

The upper red arrow shows the morning sun coming through a valley to hit the site. I included only enough terrain to account for what would block the sun. In this case, I made things contiguous because of the importance of the valleys for morning and afternoon sun - and left town in just for context.

By zooming out like this, you can see better what I meant about the low polygon count from GE. This results in some pretty rectangular looking patches of illumination, and at times, fairly geometric shadows.

Cheers,
Kalr

[Rod Jurich]

Rick wrote:
/.......
His web site is http://susdesign.com/tools.php and there is a sun angle tool, and others that might be helpful.

Excellent, many thanks for the link Rick

[Karl Ottenstein]

Here's one at Schweitzer Mountain Resort in Sandpoint showing the use for determining views and/or just giving a client a bit more realistic OpenGL walkthrough. Home design is by a friend, but I did the GE stuff for him.