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# Change the geometry of building in idf file.

When I use the Multi-family Residential Prototype Building Models, I found that the coordinate of the roof is weird. For example, the coordinate of Roof_left is:

41.122974000000,4.107433182722,7.920000000000,  !- X,Y,Z ==> Vertex 1 {m}
41.122974000000,-15.731187000000,7.920000000000,  !- X,Y,Z ==> Vertex 2 {m}
41.122974000000,-5.811876908639,12.046992000000;  !- X,Y,Z ==> Vertex 3 {m}

But the coordinate of ceiling_unit1_FrontRow_MiddleFloor is:

0.000000000000,0.000000000000,5.332900000000,  !- X,Y,Z ==> Vertex 1 {m}
12.178962909315,0.000000000000,5.332900000000,  !- X,Y,Z ==> Vertex 2 {m}
12.178962909315,9.157114969410,5.332900000000,  !- X,Y,Z ==> Vertex 3 {m}
0.000000000000,9.157114969410,5.332900000000;  !- X,Y,Z ==> Vertex 4 {m}

I think the coordinate of Roof_left should be:

0.0,19.8386201827,5.332900000000,  !- X,Y,Z ==> Vertex 1 {m}
0.0,0.0,5.332900000000,  !- X,Y,Z ==> Vertex 2 {m}
0.0,9.91931009136,5.332900000000;  !- X,Y,Z ==> Vertex 3 {m}

Why the Prototype Building Models have this kind of roof coordinate? Following is the link to these Residential Prototype Building Models. https://www.energycodes.gov/developme...

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I suggest you give a direct link to where one can download the specific prototype building you're using. Personally I'd take a quick look if I didn't have to look for (and guess) which specific IDF you're using

( 2019-11-27 08:01:24 -0600 )edit

Thank you. I'll upload the idf file.

( 2019-11-27 08:31:46 -0600 )edit

This should be a public file, so a link to it would be more appropriate.

( 2019-11-27 15:17:13 -0600 )edit

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This is due to the fact that the attic zone was not using the (0, 0, 0) origin in this case (see below). If you move this origin location to (0, 0, 0), you will be using the coordinate you specified, and move other roof surfaces accordingly. However, under the current attic zone origin location, the current coordinate for the roofs is correct. This has NO impact on building energy. In fact, if you open the model with the Sketchup plugin, there is nothing wrong with the geometry.

Zone,
attic,                   !- Name
0.0,                     !- Direction of Relative North {deg}
-41.122974,              !- X Origin {m}
15.731187,               !- Y Origin {m}
0.0,                     !- Z Origin {m}
,                        !- Type
1;                       !- Multiplier
more