{"id":264,"date":"2023-08-21T00:30:29","date_gmt":"2023-08-20T22:30:29","guid":{"rendered":"https:\/\/easyrevitapi.com\/?p=264"},"modified":"2023-10-22T14:24:16","modified_gmt":"2023-10-22T12:24:16","slug":"solids-and-transformations","status":"publish","type":"post","link":"https:\/\/easyrevitapi.com\/index.php\/2023\/08\/21\/solids-and-transformations\/","title":{"rendered":"Transforming solids"},"content":{"rendered":"\n

When using the Revit API, we often perform tasks involving multiple geometries. For instance, we might compare their positions or identify their intersections. However, it’s important to note that even if these geometries appear close in the Revit 3D space, they could be related to different coordinate systems. In this case, comparing these geometries while referring to their respective coordinates might give us incorrect results. <\/p>\n\n\n\n

I once had to write a script that checked whether MEP elements from a linked model had the exact same position as those in the host model. Curiously, even when Revit displayed all elements to be aligned, the script’s results expressed the opposite. I eventually figured out that each model positioned its elements differently in relation to the internal origin, leading to incorrect results. Although, the elements of both models had the same position to the project base point, which explained the visual alignment. <\/p>\n\n\n\n

A way of solving similar problems is by using the revit transformations and applying them to the geometries. They allow to convert a geometry’s coordinates from one system to another. Beyond this case, transformations are also useful to simply move a geometry within one same Revit model, with no consideration to multiple coordinate systems.<\/p>\n\n\n\n

Before going further, you might want to understand more about Revit transformations. For more insights, please refer to the preceding article : Revit Transformations Made Easy<\/a><\/p>\n\n\n\n

Moving the solid<\/h4>\n\n\n\n

For a better understanding of how transformations are applied to geometries in Revit, let’s consider a simple example : translating and rotating a wall. We begin by defining a method that takes the wall’s geometry as an argument, applies the desired translation and rotation to it, and then returns the resultant geometry. We’ll name this method TransformSolid()<\/mark>.<\/p>\n\n\n\n

We will be using three classes provided by the Revit API :<\/p>\n\n\n\n