CAD, BIM & 3D

This is a short post, to elicit discussion. It was written in the context of IFC-bashing and people insisting that only the use of proprietary data formats gives reliable results. As I’m not the shouting kind, I like to answer in another format… by posting some things I learned about IFC.   The more I study the data scheme, the more I see things I did not know or not understood fully. And I dare to consider myself as an IFC-expert, up to a certain level. Here it goes. These are 10 concepts supported by IFC, but which your BIM-software may not even be capable of interpreting. 1 - Revision Control http://www.buildingsmart-tech.org/ifc/IFC4/final/html/link/revision-control.htm Each object in an IFC model can evolve continuously over the lifecycle of a project. They can be marked with a Change Action , a TimeStamp and other attributes, captured within the IfcOwnerHistory property. In many BIM-software exporters, only a single Owner History is exported, so this only indicat...

This is part 6 of a series of posts about getting BIM data into Unity. In this post, we’ll discuss how we can display our parsed metadata, which is now attached to our GameObjects, on-screen. Picking objects on screen with Raycasting Unity uses Raycasting , which shoots a finite ray into the scene, as the connecting line between your 3D camera position (your viewpoint) and the point you click on-screen, which can be translated into a 3D position on the viewing plane. That ray can intersect geometry and it will return the item you clicked on, alongside the position and orientation of the hit point. But not every geometry can be “seen” by such a Ray. Preparing geometry for selection To be able to select an object you need two things: geometry to click on and geometry you can see. In most Game Engines, these things are not equal. In Unity, you can have a Mesh component, which carries the Mesh data (vertices, faces). In addition, there is a Mesh Renderer , which ensures the mesh ...

Introduction When Manufacturers create custom objects for use in BIM software, they often want to embed as much relevant information as possible into the objects. In BIM-software such as ARCHICAD or Revit, you can do this fairly easy: ARCHICAD supports Custom Properties and Revit has Project or Shared Parameters. The basic concept is more or less the same: you define a property set and individual properties inside the set, with a data type and possibly default value. To make these properties available for the user to enter, you can attach them to an element category (like wall, slab, beam, window). So far so good... The problem However... a category applies to ALL instances of elements of that category. Every single element will gain the properties assigned to the element category. So if you start loading manufacturer objects for e.g. doors, every single door will gain these new properties... even those for which this is not relevant. Managing Properties inside Autodesk Revit ...