Geometry gym allows several ways in which to use user preferred units and works with either Imperial or Metric units. For structural analysis, there are two scaling factors which are applied when exporting, one for the measure or length units and one for loading units. This allow you to work in any unit system you desire.
In order to allow this typically a two fold scaling occurs, one at input and one at export. The one at input converts your working units back to the units that geometry gym uses in the background (SI) and the one at export converting into desired analysis units.
When exporting (baking) into an analysis software package, units can be converted again into the desired units of that package. These settings are generally defined by right clicking on the bake component of each analysis plug-in as shown below.
For measure units, Geometry Gym will automatically detect which units you are using in your rhino file and apply the scaling factor as required. Note: that you will need to be consistent with what units you are using within each script.
I.e. If you are working in meters in Rhino, every input should be in meters in Grasshopper, including inputs for profiles and the like.
For load units, a specific reference cannot be made from Rhino. Therefore, a units input is specified on most of the load components. This again provides the ability to use any type of input loading units. The image below explains the basic concept.
Typically structural analysis software run on a simple co-ordinates system. It is rare that a structural analysis program will allow the input of a shared co-ordinates provide a model positioning system.
If importing a model from an external BIM software application it is sometimes recommended that a model be transposed into a more preferable position for modelling and axis alignment close to the origin.
If you are having trouble with model positioning please contact us to assist.
Some analysis packages allow you to provide local axis systems for the definition of nodes and members.
This can be helpful for geometrically complex arrangements.
A lot of structural analysis programs allow for the definition of levels and or grids.