Open Manifold Blocks - Flip Block Surface Orientation

This command applies only to open manifold blocks imported from BIM models. It can be accessed from the Edit screen when at building level when an open manifold block is selected or when at block level for an open manifold block. Using the Ctrl-F keyboard shortcut is the fastest way to start the flip block command.

 

Open manifold blocks cannot use all geometry operations and the surface orientation cannot be reliably determined from the model. DesignBuilder must rely on the orientation data stored with the surface from the BIM model. This data is not always reliable and so in some cases surfaces come through into DesignBuilder facing in the wrong orientation. The Flip block surface orientation command can and should be used to check and, if necessary fix, the orientation of surfaces in all open manifold blocks.

 

When the Flip Block Surface Orientation command is active you can click on the surfaces in a block to see their orientation. You should see the red arrow pointing outwards away from the centre of the block as shown below.

 

 

Some surfaces may be facing in the wrong direction (inwards) and will often be seen in white looking from outside the block as shown below.

 

 

Clicking on these surfaces shows the arrow pointing inwards. In this case press the Shift key while left clicking with the mouse to flip the direction of the surface to make it point outwards. The image below shows the fixed block looks after the Shift mouse click was used to flip the surface orientation.

 

 

All such inward facing surfaces must be flipped to ensure an accurate model before using it to run energy simulations. Otherwise inward-facing surfaces will have the wrong orientation in energy simulations.

 

Note: even when all surfaces in open manifold blocks have been correctly flipped these models cannot be used in Radiance daylighting and CFD calculations which require all blocks to be closed manifold.