Modeling in Ecotect

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Short Cuts

Modeling Principles

Ecotect is a (somewhat) complete modeling environment. Feasibly, any model can be constructed within the ecotect environment using its own internal drawing commands, extrusions and other modeling features. Models produced in ecotect will not only be cleaner, but will respond with more fidelity to all statistical methods of analysis. Imported models will universally fail, unless special care is taken to establish each piece of geometry as floor/wall/window/door/aperture. Ecotect will not interpret this on its own with an imported model. Below are some basic modeling principles that will result in the most useful model for both statistical and geometric analysis.

Level of detail

An appropriate thermal model

An appropriate lighting model

Models must be well-calibrated to the desired analysis. In the examples to the right, we see a rather primitive model that is the best choice for thermal analysis. Simplicity of volumes allow ecotect to understand general volumes and most importantly shared adjacent surfaces. The geometry is kept simple to keep the calculations quick. The second model, much more intricate, is more appropriate for a lighting study. Since the extra surfaces would act to shade and otherwise change the light levels, and since lighting calculations would not be over-complicated with extra geometry (due to the mathematics of ray casting), we are free to implement more detail.

Modeling openings

"C" shaped window

Ideally, windows and other apertures would be modeled within Ecotect as parametric "child" objects. If you choose to model them in Rhino or another modeling software, you can draw walls with apertures as "C"s so that ecotect is able to interpret both the wall and the opening. This will not work well with statistical methods, but will work for geometric analysis.
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Modeling zones

Fully enclosed zone

Interzonal adjacency with model and outside earth zone

For acoustic and thermal analysis methods, we need to properly set our object up as a series of perfectly enclosed zones. Enclosed simply means that there are no open faces. Modeling in ecotect, this will be a natural condition. Importing a model might force you to reconstruct certain surfaces to ensure closure, especially if you are analyzing a small part of a building with potential connections or opening out to un-modeled areas. You can establish your own zones, seperating out the model into discrete rooms. Ecotect automatically creates an outside zone which it will use to consider thermal transfers between your building, the air and the earth (any part of your model below the 0'-0" level will be considered underground, interfacing with the ground - see the diagram at right).

Modeling Adjacency

Double modeling overlaps

Adaibatic surfaces

For thermal calculations, we must be careful to spell out how two spaces share surfaces. For two rooms that are both a part of our calculations, we must model them separately and ensure that the shared walls are co-planar. This will allow ecotect to understand them as a shared wall, which it will determine during the interzonal adjacency check, performed at the outset of many statistical caluclations. The same principle governs for cases in which we wish to have a shared surface with a room that we are calculating and another that we are not. By establishing one room as a non-thermal zone, the shared surface will be considered "adiabatic", meaning that no heat transfer occurs across the surface.

Importing Principles

You may import from autocad, 3d studio, rhino, or any other CAD software through DXF, 3DS, and OBJ files. DXF are best for approximating the surface geometry. Ecotect can handle any kind of polygonization, but many calculations are more sensitive to the number of polygons than their complexity, so it is best to merge faces that are co-planar after importing. Accomplish this by:
"Modify"... "Merge Coincident Triangles...."

Statistical Analysis of a Simple Building

Here we will model a simple scenario of interconnected rooms that have a variable relationship with the ground. This will challenge us to properly handle zones in such a way that we can run a thermal analysis on the space.
Example file here

Modeling

Changing Snap Settings

• Setting up Snapping options
  • By clicking on the Snap icon (the magnet), you may change which features get snapped to. This works similar to other CAD softwares.

• Drawing a Zone
  • Under Draw select Zone
    • Click several points on the model, establishing the boundaries on the zone
    • Press ESC to exit drawing, it will automatically close the zone
  • Go to the Zone management pane (to the right side of the Ecotect window)
    • Ensure that your new zone is there, and make sure the T icon, indicating a thermal zone, is enables
  • Draw another zone, using the same method, but snap to the existing zone that we can create an adjacent surface.
• Adding Child Objects
  • With a face of your zone selected...
    • Under Draw select Insert Child Object OR press Insert
    • Select the type of child you want, in this case
  • You may also...
    • Under Draw select Void
    • Start to draw an opening the same way you would draw a shape. The shape will be anchored to the face. You may need to hold CTRL while hovering over a point to move the insertion point above or below the 0'-0" elevation

Loading Weather Data

Loading weather data

• Import weather data file...
  • Under Model select Date/Time/Location
  • Click load climate data and select new york new york
  • Allow ecotect to change the global position to match climate file

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Adjacency Checks

Adjacency Sampling

Adjacency checking allows ecotect to understand how parts of your geometry are shared across multiple zones. Even if you have a single zone, ecotect must understand how it touches the outside zone - it will use the calcs to base simple thermal analysis equations.

• Checking for Adjacency...
  • Under Calculate' select Inter Zonal Adjacencies
    • Adjust sampling accuracy to high
    • Adjust surface adjacency tolerance to close
    • Make sure Perform Detailed Shading Calcs is enabled
    • Press OK

You should see the model being overlayed with a series of sample points. Adjacent surfaces (including adjacencies to the ground plane) should become highlighted with larger dots.

• Fixing errors...
  • Make sure your zones are constructed from closed objects. Also ensure that shared faces are double-counted and that they are well-modeled (facing outwards, in the same plane, and extremely close together).
  • Sometimes, modeling using the zone command rather than extrude will fix errors. Try tracing over your original model.

Thermal Analysis

Thermal Analysis Example

• Setting Zone HVAC...
  • Under Model select Zone Management
  • Click on the appropriate zone
  • Cycle through options under HVAC System
  • Cycle through options under Occupancy
  • Do this for each zone and press OK
• Calculate
  • Under Calculate select Thermal Analysis
  • Follow the wizard. Initially just try calculating Temperatures.
  • The window will automatically shift to Analysis view and show you a graph of hourly temperatures.
  • Under Display select Zone Temperatures to see an overlay of the zone temp on the model. This can be exported to Illustrator or captured as an image.