LEED Credit SS7.1 and Revit

[rtaube]

For LEED Credit SS 7.1:
Is it possible to create a Tree family with an Area Parameter for the Shade which interacts with the hardscape to provide a "shaded area" which can then be scheduled? I'm not doing this for a current project, was just thinking that the idea would be cool, but the execution seems a bit mind boggling to me. Below is the credit requirements.

Intent:
Reduce heat islands (thermal gradient differences between developed and undeveloped areas) to minimize impact on microclimate and human and wildlife habitat.

Requirements:
OPTION 1
Provide any combination of the following strategies for 50% of the site hardscape (including
roads, sidewalks, courtyards and parking lots):

[Alfredo Medina]

How would you deal with date and time of the day? Azimuth, altitude, shape of trees, etc?

[cliff collins]

Perhaps this could be done with a Solar Study--using 3D Trees to cast shadows
at various times of day/year and demonstrated in an .avi movie for LEED?

The 2D tree with a filled region is not the answer.

cheers

[mthurnauer]

It would take some experimentation, but it would seem that the avi could work, but probably more realistic is to do a select number of plan-view stills. With shadows set to black in a hidden line or rendered view, it may be possible in an image editing program to get an interpretation of average pixel value.

[rtaube]

My understanding of LEED 2009, is that it needs to only be calculated on June 21, at solar noon. I think the shading area for a particular tree would be known beforehand, it would just be a graphical matter of showing where that shadow falls on the plan. As the shadows would fall to the north (if one is north of the tropic line), perhaps the distance between the center of shadow and center of trunk could be calculated based on formula involving the latitude. The orientation of the shadow would be based on where North is. The question would be, how to calculate a Boolean area, where you only count the overlap of the "shadow area" and the "paving area" I don't see how this could be done yet.

[cliff collins]

Yes--all that might be able to be done with a 2D family, but a solar study (still shot) render from top view with sunlight, day/time/year/location and 3D foliage might still be a better choice.

just my 2 c worth

cheers

[rtaube]

I agree that 3D foliage would be a much better choice, but I don't know how one would calculate that 50% of the paving is covered in shadow.

[cliff collins]

The paving could be made with floors or subregions of a toposurface, and a schedule of area generated for shaded and unshaded portions.

cheers

[rtaube]

Cliff, could explain how the shadow area calculation is done a little bit more in depth. I had no idea that was even possible...

Thanks,

[cliff collins]

I have not actually tried this, but here's a possible scenario:

1. Create a Site Plan, with a toposurface. Split up the toposurface into Subregions,
showing hardscape (paved areas) and green areas (grass/planters, etc.).

2. Place trees ( Deciduous RPCs, for example ) where needed to provide shade on the hardscape portions.

3. Render a 3D camera view, with Top orientation from the View Cube. Specifiy the LEED required Jun. 21 date/time in the render settings.

4. Save an image ( tiff or png, with transparency ) from the rendering, and then insert
and scale it onto the Site Plan view.

5. Noting where the shadows fall, adjust the subregions on the toposurface to align with the boundaries of the tree-shaded areas.

6. Create a new Schedule,showing the areas of the subregions which are shaded by the trees. ( if subregions don't work well and /or schedule properly, you could use Floors.

As another option, and to skip the render>place image steps above, you could just use a shaded or realistic view with shadows turned on, making sure day/time/month was set correctly. The RPC trees will cast shadows which will look a bit odd, since they are not rendered. You could create a "symbolic" tree family with a trunk and foliage mass instead of using the RPC trees.

Again, I have not tested this work flow, but in theory it should work.

cheers

[nancy.mcclure]

I think Mthurnauer's approach would be the least painful: Create the shading elements, set your site plan view to the appropriate date/time, export out as an image file. A photo editing software (Photoshop, Aperture, maybe even iPhoto) would have the ability to assess a percentage of the overall image based upon color/gradation. Probably require painting the image area of outside the property line with a 3rd color (blue, for example) and Bldg footprint a 4th color (red)... to get it's percentage to subtract from the whole.
Image = % blue (outside Property Line) + % red (bldg area) + % white (non shaded area) + % non-white (shaded area).
LEED calculation (shaded area) = Image - (% blue + % red) / % white = hopefully over 50%

Interesting query - thanks for giving us a new puzzle to chew on! ;)

[twiceroadsfool]

You can do it by scheduling the planting families, if you put in a few shared parameters to calculate the approximate shaded area. ALl of these methods will be approximate, regardless. If you want, you can even add in a parameter in to the planting for solar angle, although it wont be tied to the project solar angle.

The nice feature about that, is you can generate a schedule for total ground covered, and you can design option the plants, and show it at different levels of maturity and/or different times of years, with the variable sizes and shader formulas in the tress.

Otherwise, go with the exported image. Messing with subregions, with a toposurface, in a site plan, with shadows turned on, and an entire site for of trees.... Youre going to eat up a 40 hour week tracing those things.

[mthurnauer]

I did a test of this method and I think it looks like it would work well. Attached are two files, one that is the site surface showing all of the paved areas in red. The second has the shadows being cast by 3d trees. I went into photoshop and in I did a Select, Color Range. I then switched it from sampled colors to Red. I opened up the Histograms and under the information it indicated 289,889 pixels selected. Important Note: The histogram had a little Asterisk icon that I needed to click for the information to update. I repeated this process in the images with Shadows. It indicated that 238,785 pixels were selected. So, divide the total by red area by the remaining red area gives you 0.82. Subtract from 1 and you have the percent shaded area. I my example it was 18%.

[gaby424]

make a fam like in picture.

in project make a horisontal floor by traceing the plan shape of your site.
duplicate the floor and hide thr copy

put the face based trees on the visible floor.

rotate the tree so the "void cutted hole shadow" is in corect direction in plan view

make a an area schedule by filtering that 2 floors. the diference = shadow area.

observation: the shadow area resulted is the projected version on an horzontal plan of real shadow area . Te same result you have with the photoshp method.