如何获取特定 IfcElement 的 material 数据

Question

在xbim示例https://docs.xbim.net/examples/basic-model-operations.html的基本操作中，它展示了如何检索特定IfcElement的单值属性。基于此，我尝试获取 material 数据。

我写了以下内容：

var id = "3NBPkknun6EuV9fpeE6rFh";

var theWall = model.Instances.FirstOrDefault<IIfcElement>(d => d.GlobalId == id);

var materials = theWall.HasAssociations
                        .Where(r => r.RelatingMaterial is IIfcMaterialProfileSet)
                        .SelectMany(r=> ((IIfcMaterialProfileSet)r.RelatingMaterial).MaterialProfiles)
                        .OfType<IIfcMaterialProfile>();

它给我这个错误：

'IIfcRelAssociates' does not contain a definition for 'RelatingMaterial' and no accessible extension method 'RelatingMaterial' accepting a first argument of type 'IIfcRelAssociates' could be found (are you missing a using directive or an assembly reference?)

我知道我必须使用 IfcRelAssociatesMaterial，但我不知道如何使用。如何检索 material 信息？

Answer 1

IIfcObjectDefinition 的 HasAssociations returns 一组 IIfcRelAssociates 但您只需要具有 RelatingMaterial 属性的派生类型 IIfcRelAssociatesMaterial。参见 https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2/HTML/schema/ifcproductextension/lexical/ifcrelassociatesmaterial.htm

因此，只需添加 .OfType<IIfcRelAssociatesMaterial> 即可将查询限制为 Material 关联。即

var materials = theWall.HasAssociations.OfType<IIfcRelAssociatesMaterial>() 
// rest of the query

如何获取特定 IfcElement 的 material 数据

How to get the material data of specific IfcElement

c#

linq

ifc

bim

xbim