By Dennis Collin
When working with existing drawings that contain 3D elements, there can be a problem in that when elements are added, they snap to 3d points, meaning perimeter lines or boundaries are no longer flat or planar. This can cause many problems with commands like Trim, Extend, Hatch and the measurement of areas. Error messages such as “Element not co-planar to current UCS” can also result in the command prompt.
This situation can be easily avoided. Set AutoCAD’s snapping tools to ignore references that are located off the current drawing plane i.e. draw in a flat 2D space only. This is achieved within the options dialogue.
Click on the Drafting tab and ensure ‘replace Z value with current elevation is ticked’. This is set to zero by default. Once enabled any elements drawn should be planar and the trim and hatch command should work more reliably. However, this process will not fix any existing drawings, to achieve that some additional routines will need to be run to flatten the drawing. I will cover that process in a future post.