Another common issue is where the gbXML is poorly defined for roof levels. When imported into the VE an additional ‘shade surface’ has been added to the model where it is not required. This can occur where there are pitched or flat roofs. (See image below) The impact of this is incorrect results from analysis performed as this shade surface is altering where the external boundary begins and is also blocking sunlight that would normally be received by the roof surface.
Images from the Virtual Environment: Rendered view with model volumes incorrectly imported from a poorly defined gbXML.
To resolve this issue new level need to be created above the roof construction in the Revit model to tie the rooms/spaces too or the offset function utilised for the roof level volumes within the model. All other volumes should be tied to levels in the model as mentioned previously to avoid overlapping. The image below shows the outcome that should be achieved.
Images from the Virtual Environment: Rendered view with model volumes correctly defined and imported from the gbXML.
Using sections and turning ‘Room/Space’ fill on is a good way to interrogate if volumes placed in the model are to the levels required as shown in the image below.
Image from Autodesk Revit: using levels to set up room/space volumes for export – section view of space volumes.
