Trimming Surfaces

Source:
Don LaCourse, Principal Partner, eDocHelp
Editor, 3DCADTips.com

Surfaces may be trimmed or divided by curves and or other surface boundaries. This is a very convenient and powerful technique to seemingly discard unwanted surface areas. However, trimmed surfaces do pose concerns for the development of solid models and for data exchange through neutral formats such as IGES and STEP.

Many trimmed surfaces in a single model will increase database size and complexity since more information is required for storage (original surface, trim boundaries, and resulting trimmed surface). Also, the resulting surface edge is dependent on the accuracy and dependability of your 3D CAD system's surface trimming functions. Air tight surface enclosures are required for solids so always check trim boundaries that are to mate with other surfaces.

[Michael_S]

I have a Steel Structural Model, built by some program I am not aware of and there are no clues in the files to find out what plug-ins may make my work easier. When I open in AutoCAD 2004, the steel model seems to exploded into 3D Faces - tens of thousand of entities, with no residual data attached.

I have a Three-story Stucture built in this model & file size is 14.6 MB! I want use it in Architectural Desktop 2004, so I want to separate the model into individual floors -- which cut filesize down to ~6 MB. I'll be using it as an xref in the end, but for now my problem is editing the model.

I have some vertical steel columns which need to be trimmed aove and below their "slab elevation". Trim does not recognize the "3D Face" as an entity to trim & "slice" does not work, becuase "slice" is looking for a 3D Solid, for the same reason, "subtract" does not work either.

What can I do? I have considered editing it's elvation properties in the properties menu despite the numbers not making sense.

What are your suggestions?

Michael_S