Hi everyone, my name is Neil Bulger and I am an energy modeler for a small design MP firm on the west coast in Oakland, CA. I’m happy to join the writing team here on the openRevit site. My focus and interest in energy modeling has been to find open-source tools that can both mold to the job required and providing enough information under the hood for engineers and owners to feel comfortable with the results.
Today, I’d like to share a neat tool I found a while back called Greenspaceslive (greenspacelive.com). The tool is a plugin that works with Google Sketchup and allows a 3D model of a building to be tagged with surface types and assigned to spaces, building a gbXML file that can then be exported to a number of various software tools, such as Trane Trace or in California, EnergyPro used for code compliance.
While this is a free tool that can create gbXML, which is fantastic, it is not without its holes, and it has some major ones. I honestly think this is a great tool, but for purposes of today, I will talk about the shortcomings and some advice. The way the program works is by creating a building first and then “painting” the model with the associated construction types, walls, roof, floor, slab-on-grade. The painting step is a one-way-process, meaning, once a wall has been tagged as a wall, even if you delete that wall in Sketchup, the gbXML database will STILL have a record of it. This can be a major problem when halfway through a building, a room does not close correctly, or a wall is actually two walls because there is no tool in the plugin to “un-paint” a surface. There is a work-around with another bug in the software that can delete a wall, but this is not a smooth process and often can lead to more trouble (see their form for more methods).
Another word of warning is to always check a few floor areas in the final software you import the gbXML into. Trace for instance, will do some strange things with floor areas. When you draw a two story building, there is 1 surface (polygon) that is both the ceiling of one room and the floor of another. If that ceiling is assigned as an Interior Floor (for the 2nd story), Trace will miss-calculate the floor area of the 1st story, adding all surface together that are considered “floors”. Again, something discussed further on their form but an easy problem to avoid if you know about it.
For the most part, the tool can save time by exporting to multiple programs and can give more people access to a 3D gbXML drawing tool for geometry. I have read on their website that they are working on several of these bugs for the next version of this software and I’m sure with more folks trying this software out, they’ll step up their efforts. Cheers everyone!