Drawing in SketchUp for analysis

November 4th, 2008 | by PetecloseAuthor: Pete Name: Pete Murray
Email: Pete.Murray@iesve.com
Site: http://iesve.com
About: See Authors Posts (1) |

What I’d like to do in my blog is provide some basic guidance with some simple hints and tips for taking your sexy SketchUp model one step further and running the likes of detailed energy consumption, Architecture 2030 Challenge benckmarking and LEED daylighting compliance analysis.  Now, I’ve had a bit of experience using SketchUp over the last couple of months but not even close to some of you “super users” so please forgive me if some of this is old hat to you.  However, and this is the point, there is a difference between the conventional way of drawing a SketchUp model, purely concerning the shell of the building and its aesthetics, and having individual rooms acknowledged for analysis eligibility.

Now, I am going to assume that you already know about the SketchUp plug-in and the room finding icons and so on and so forth (if not, please go to the SketchUp link on this website or go to www.youtube.com/IESVE).  All I’d like to do is help you to get your model ready quickly and efficiently to streamline the process of analysing your building design.

Right, let’s cover the basics first, and then we can apply it to something relevant. You may have seen some of this in the literature, but I’ll assume you haven’t.

The first movie clip shows the basics of room creation and how the room finding algorithm finds spaces based on surfaces.

Once the 2nd room is extruded, you will see there is no floor. The fundamental rule for “rooms” to be acknowledged is they must be enclosed volumes. These have no floor, hence no rooms are found.
Drawing a line across the floor will then bound these spaces with the floor and also a partition wall. 2 rooms are found.
I don’t want a partition wall, so I’ll delete the surface. Woops! Only 1 room is found now.

I’ll draw the surface back in by adding a diagonal line to bound it, then delete the diagonal line.

This time, instead of deleting the surface, I’ll make the surface 0% opacity and it will be picked up as a partition, albeit an invisible one, but at least light, heat and air can pass through it. Ah ha! Now I have 2 rooms again.

Ok, so that fundamental rule  is that to divide spaces into separate rooms, there must be a surface connecting them, then the levels of opacity will determine whether they are walls, windows, or holes.

0%          hole
1-99%    window
100%     wall

Ok, let’s take that rule and apply it to my design.

1.  We shall assume we have the floor plate but no individual spaces.  If you want to know what the heating and cooling loads are for each of the rooms, not the whole floor because they have 1. Varying space usage and 2. Different orientations and hence varying solar penetration.

2.  One of the spaces is in an open plan office but it’s very large so we want to split the space into perimeter and core, but maintain the space as open plan for solar tracking and heat/air transfer purposes.

3.  So the steps shown in the 2nd movie are as follows.

a.  Floorplate with no floor, no room found

b.  Floor drawn, room found

c.   Partition walls drawn to define enclosed office spaces.

d.   Core and perimeter spaces drawn

e.   Partition walls modified to have 0% opacity therefore in any subsequent analysis, light, heat and air can pass through into the adjacent space, but each room is considered its own entity from a load perspective.

The next step will be to run this model through the likes of VE-Ware (our free tool), the VE-Toolkits and modules within the full Virtual Environment. This will allow you to gauge its performance in terms of daylighting, airflow, energy and thermal comfort. And you thought your sexy SketchUp model was just for show eh. Wait ‘till my next blog.

Pete M