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overhang Angle error in openstudio

asked 2016-06-29 09:25:32 -0500

shahin1992's avatar

updated 2016-06-29 11:09:15 -0500

i'm trying to study the impact of different overhang size and angles on the building energy consumption using openstudio program but evergy time i save my model, openstudio only saves the angle for the first two floors while the rest are being moved. the Steps are as follow:

1- first creating the overhangs using the plugin.

2-rotating the overhang 10 degrees.

3-the first two floors get done well while the others are being moved from their original location.

OS File

I start by this

then i rotate the south Overhangs 10 degrees

this is the desired outcome model

while this is what i get when i save the openstudio model and run it

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answered 2016-06-29 09:52:43 -0500

updated 2016-06-29 10:34:57 -0500

On the first two floor you went into the shading surface group, selected the surfaces, and then rotated the surfaces. On the other floors you instead selected the surface group and rotated it.

In OpenStudio surface groups (as a group) can only be rotated along the z axis (horizontally). There is no place to store rotation on x or y axis. There isn't a way to prevent SketchUp from letting you do this. At one point in time we snapped it back right away so you get some feedback, but that doesn't happen any more, can't remember why we changed it but my guess is to improve performance. As a result it looks fine while working on it, but then shows up in unexpected location when you re-open it, which I agree isn't ideal.

The solution for now. If you just want to move a collection of surface groups, or rotate horizontally, that is fine; but if you want to rotate them in non-horizontal way, then go into the group, select the surfaces that you want to rotate, and, then rotate.

If this is a common thing you want to do, it would be pretty easy to write a measure that takes the outer edge of shading surfaces and lowers the z vale by a user specified amount (not exactly same as rotating, but maybe fine).

Update - Added images related to comment on editing multiple overhangs at once.

image description I created a single building shading group, drew one surface, and copied up multiple times.

image description I then selected the outer edges and moved then down along the z axis. You can also then move them on x axis to shorten the surface back to it's original length.

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It seems to me that if you just lower the z value without modifying the x/y values, you will "stretch" the overhang making it longer than original?

Chris Jones's avatar Chris Jones  ( 2016-06-29 10:18:38 -0500 )edit

@ David that's true, that actually worked although i've to do it one by one though! i would love to write a measure but i'm very beginner at this and i've no programming experience but i plan to take openstudio and energyplus as a first step for now and start ruby programming as soon as i get familiar with the first two and be able to do all the basic stuff first through my college assignments. regards, Shahin

shahin1992's avatar shahin1992  ( 2016-06-29 10:22:33 -0500 )edit

@Chris Jones, that is correct, but in some cases users may want the projection length fixed with a variable z offset. If you wanted to truly rotate it you could do that, would just take a little more code.

David Goldwasser's avatar David Goldwasser  ( 2016-06-29 10:24:24 -0500 )edit

@shahin1992. The create overhang by projection factor results in a shading group with a single shading surface for each window it is applied to. If you want to you can manually make a single shading group at the building level with multiple shading surfaces. You could draw one surface, then make multiple offset copies of it. Since they are all in the same group you can select the outer edges all at once, and then move them down, and then optionally horizontal to shorten the overhang to correct length.

David Goldwasser's avatar David Goldwasser  ( 2016-06-29 10:28:14 -0500 )edit

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Asked: 2016-06-29 09:25:32 -0500

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Last updated: Jun 29 '16